DRFIX  Having used some free, and other paid FTP solutions, I found the Rumpus demo and decided to "give it a try". Man, am I ever glad I did! I've precious little time to fiddle with configurations and Rumpus allowed me to get to work with less downtime (read...money!) and frustration (i.e. grey hairs).

Rumpus installs quickly, cleanly, and you can install it on a remote machine on the LAN etc. to manage most of your admin tasks. The interface is clear, logical, and consistent as far as any FTP server is concerned. Group folders, where you can assign users their particular access privileges, is a nice bonus.

The Web management interface is a big plus for end users who haven't a clue about FTP clients etc. (Like you've never run across these people before!) This makes the FTP client/support issue a moot point. Now I can send a link to people and point them via browser and not have to explain for the millionth time what FTP is. Saves everyone the frustration and I don't have to bear multi megabyte files choking my email system.

While its certainly not "cheap" I do believe the old addage that you "get what you paid for" holds true. If I paid myself for the time spent diddling with other solutions I more than paid for this several times over. Email questions are responded to in a timely and courteous manner and that says a lot to me. Kudos!  
(Version 5.0.7)

DRFIX  I'd searched high and low for an email server that wouldn't require me to be a full time administrator. Many, while free , took too much of my time away from other tasks in order to manage or study up on, and others were so expensive as to put them out of reach of mere mortals(ex: CGP).

KMS was, for me at least, approachable and easy enough to understand that it took little time to configure a working SMTP/POP/IMAP server with options. To get the full benefit did take some time to pour over the documentation because, to be quite frank, there are some areas that simply are not explained very well or at all.

That being said I've been more than impressed by its stability and only wish that Kerio had a more liberal upgrade policy because you either get locked into their "subscription" or pay nearly the full price over and over and over. For larger enterprises I can see the benefit but for now I'll stay with an albeit "older" version but one that works.

This is a good product and I look forward to where its headed.  
(Version 6.3.1)