I've been a user of Interarchy (nee Anarchie) since version 1 sometime around early '94. Back then, I was a college student running a small software company, and I used the program enough that I was at its highest usage rating (it rated the type of user you were--such as "novice"--based on the cumulative amount of data you'd transferred). I believe the rating was Net Fiend, but I could be mistaken.

The landscape has changed much since those days. Today, I'm a professional web developer and Mac software programmer, and use and depend on FTP clients day in and day out. And, of course, FTP clients are no longer restricted just to the FTP protocol; they're asked to interface with servers through a whole slew of protocols, as well as implement advanced functionality like mirroring. And yet, through all this change, I still use Interarchy. In fact, it's one of only two programs--the other being BBEdit, which IIRC came out on my birthday in 1993--that have consistently remained essential tools in my toolkit.

In the early 1990s, your choice of FTP client was realistically limited to Anarchie and Fetch, from Dartmouth. I regularly checked out Fetch, and though it was a fine program, always returned to Anarchie. Since then, numerous other clients have come along. Being a good pro, I have checked them all out periodically, especially around major version releases. Some of them are quite nice in what they offer, but none has matched Interarchy for its total package of power, flexibility, efficiency, and reliability when it most counts.

I mentioned BBEdit. Interarchy is very much like BBEdit in that both programs offer extremely deep feature sets aimed squarely at professional users, and both are backed up by unparalleled support from companies with long, rich, Mac-only histories (and both originally created by guys who are pillars of the Mac software development community). Yes, both programs cost more than their competitors, but packing great engineering into great packages backed with great support isn't cheap. Also, keep in mind that paid upgrades are typically years apart, which contrasts with other software for which you likely pay every 12 months or less.

In short, if you only rarely need the tools that Interarchy provides, you're probably better off with something less complex and less expensive (or free). Fortunately, the platform now boasts a ton of good choices for casual users.

OTOH, if you are an alpha-geek OS X power user or a professional reliant on file transfer and networking tools, give Interarchy a look. And not just a casual look, either - dig deep. Read the manual, use the software heavily for the duration of the free trial, check out the community, and figure out how to modify your workflow to take full advantage of it. Trust me when I tell you that you won't regret the effort.