If you've ever watched an e-mail application choke on a 4MB attachment, you know that sometimes you need an alternative to directly sending or receiving files. And if you've ever e-mailed a crucial file that never arrived at its destination, you'll want a way to transfer files and make sure your recipient received them.

File Transfer Protocol (FTP) is tailor-made for quickly moving large digital files between a remote computer acting as an FTP server and an FTP client that lets you access and upload those files. And there are now several excellent FTP clients for Mac OS X.

We evaluated seven FTP clients available for OS X: Fetch Softworks' Fetch 4.0.3, On-Core's SimpleFTP 2.01, Panic's Transmit 2.5, RBrowser's self-titled RBrowser 3.1.2, Stairways Software's Interarchy 6.2, Vicomsoft's FTP Client 4.0.1, and Xnet Communications' CaptainFTP 2.6. We also considered how these programs stack up against OS X's Finder, which you can also use to connect to FTP servers. If you want to download files from an OS X–based server, the Finder may be all you need, but it won't let you upload files. All seven programs performed solidly, but two programs with advanced features and intuitive use came out on top: Transmit and FTP Client.

The Basics

FTP clients should be able to connect to common FTP server types, such as AppleShare IP, Data General, Quantel Hal, Serv-U, Windows 2000, and WU-FTPD. All the FTP programs we reviewed can upload and download files from these FTP server types, in standard FTP mode and Secure FTP (SFTP) mode.

Beyond that, even a rudimentary FTP client should have some file-management capabilities, be able to move and delete files from the server, and keep a list of bookmarks for quick access to different servers. In addition, an FTP client should let you set permissions for each file, so you can determine who can view it (read), make changes to it (write), run it (if it's a program), or search it (if it's a text file). All the clients we evaluated included these basics, but some outperformed others.

Ease of Use: The Interface

We looked for programs that closely integrated themselves into Mac OS -- that mimicked the Finder, supported long file names, and allowed drag-and-drop file transfers. Although Fetch was once the standard FTP program for the classic Mac OS, its inter-face has barely improved since its conversion to OS X. Fetch's interface is easy enough to use: clicking on the Get button in the browser window downloads the selected files, and clicking on the Put Files button uploads files to the current directory. However, many people may find this language confusing ("put" what where?).

Interarchy has been around almost as long as Fetch, but it has embraced OS X's navigation style. Like FTP Client, Interarchy lets you view files in list and column views. Interarchy shares a lot of interface conventions with Web browsers, including an editable location field, which displays the current file path at the top of each window.

SimpleFTP's interface is similar to Fetch's -- it has a browser area for getting around on the server and two buttons for uploading and downloading files. But while Fetch and SimpleFTP have clean interfaces, they lack other file-management features such as the ability to intuitively move files between different directories (folders) on the FTP server. Their drop-down navigation for moving up a directory structure is cumbersome, especially since moving down a directory structure requires clicking on folder icons instead.

In many ways, RBrowser is the most OS X–like of the FTP clients we reviewed. It lets you switch between three view modes (Icon, List, and Columns) so you can view multiple levels simultaneously. And its navigation is like the Finder's, so it's easy to use. But you can't resize columns in Columns view, which is frustrating because you can't fully view long file names.

FTP Client gives you two OS X view modes (List and Column), but in Column mode, you can't drag and drop directly from the desktop to upload files -- a major drawback. Vicomsoft reports that this is a known bug in OS X and that Apple will correct it in future releases, but there's no such problem in RBrowser's Columns mode.

At first, the interfaces of Transmit and CaptainFTP seem very similar. Both let you browse your Mac's files and the remote FTP server at the same time in side-by-side browsers; FTP Client does this, too. This layout makes it easier to manually synchronize files and make sure that the application's automatic sync feature is working properly. However, Transmit's interface is intuitive, while CaptainFTP's interface is quirky -- many of its buttons have inscrutable icons. If an easy-to-use interface is your highest priority, Transmit is the way to go.

Workflow and Synchronization Features

Key to any FTP client is a well-implemented bookmark feature. If you can bookmark servers and directories within a server for quick access, you can significantly speed up your workflow and store not only complex server addresses but also user IDs, passwords, and other important settings.

Transmit outshone the other applications, with its integrated and understandable login dialog box, which included both a drop-down menu for bookmarks and a drop-down menu for accessing other computers on the network via Rendezvous. This lets you easily connect to any Mac on your local network for quick file transfers. Although CaptainFTP has a similar feature, Transmit puts it up front.

All of the clients except SimpleFTP let you make the contents of your local and remote directories match. Most let you do this in just a few clicks.

File synchronization is FTP Client's strong point. Only FTP Client has the ability to create FTP droplets, which let you use drag and drop to quickly perform an action. Select a folder on the FTP server, choose Bookmark: Save As Droplet (1-D), give the droplet a name, and then save it somewhere handy. Whenever you need to upload a file to that folder, drop it on the droplet icon. The droplet automatically runs FTP Client, logs on, and uploads the file.

Previewing and Editing Features

Transmit can show you the content of any file. You still have to temporarily download the file (which starts automatically when you click on it), but seeing the content before committing to downloading files is nice. For example, if you're searching for a particular HTML file, you can scan through several files, viewing the code in the preview pane, to find the one you're looking for -- without having to download and open each one independently.

Unlike the Finder, which will preview images in the final pane of column view, Interarchy will display only the file icon and file information. It lets you preview, but not edit, text files in TextEdit. However, as with Transmit, you can edit files in BBEdit (if it's installed).

Fetch, too, has some great features for previewing and editing graphics and text files before download, but they're hidden in menus, not an integral part of the interface. For example, to preview a graphics file, you need to click on the file in the browser and then select Remote: View Media File. A separate window will open and display the image -- producing more screen clutter.

RBrowser shows the most promise with editing remote files. Although the other FTP clients let you edit remote files, only RBrowser lets you use any available application on your computer. However, this feature is accessible only through the Info palette or with the menu command File: Open In Application (and then you have to choose the application). Both methods require several clicks.

Macworld's Buying Advice

You have several excellent options. Transmit is the easiest to use and most powerful FTP client available. We appreciated its intuitive interface, excellent features, and solid performance. FTP Client, too, has a well-designed user interface and provides exceptional performance. It also gives you the ability to create fast access droplets, which, if you regularly upload files to the same place, can be invaluable.