Wow... your choice are all pretty much the same. Seems like it's also the same at WHT: Always either eSupport or PerlDesk. I've tried PerlDesk, and don't like it. I don't like a lot of things coded in Perl, but even putting that aside.. it wasn't the best available for how much you paid. I'm sorry, but there is better available at that price.
Kayako eSupport... it's good looking, but it's not the best either. It's got lots of features, and great ones at that. Maybe I've no tried hard enough, but to be honest I've barely tried, but I'm unable to make it so my clients have to log in to submit a ticket; which I think is very important. I've a form for people to submit if they're simply contacting me, but each client has their own account number, and due to various different packages with different levels of support, I need it that clients are logged in.
SSM - It's free, very easy to customise, and is practically perfect. It's still beta, and has a few bugs, but if they got it out of beta and fixed the bugs it'd be perfect. The only problem is in Mozilla 1.7 you cannot submit large tickets; and I don't want to make my clients use a different browser. I had one test it out in Opera, and it's perfect without problems... yet Mozilla constantly has errors.
phpSupport - Great. It's free, under the GNU license, works great and has plenty of features. What I don't like about it? When sending out e-mails to clients saying "Your ticket has been responded to", the from address is
support@servername.com - Not the best IMO. True, it tells the clients which server they're on, but I'd much rather it be
support@company.com
OneOrZero - Tried it. It was ok, not the best, and IMO SSM was much better, and so was phpSupport, however I must say from what I can remember it's the only one that didn't have those errors.
I've tried plenty of others, actually personally, and seen the demo of many. In fact I've downloaded and installed Mozilla 1.7 and am testing plenty of help desks with it to make sure there are no errors; as it just happens the majority of my clients use Mozilla as their browser. :-/
I'm currently testing out Support Logic; seems so far pretty good, but we'll see. Also another good one is Flextic, or so it would seem from their demo. I've found two GREAT help desks... the only problem is that they only work on a Windows environment, meaning I can't use 'em because I've only Linux servers.
I've found another which is 12mb.. but it's a full thing, client database, client support centre, internal centre for your network so employees can contact each other I
think. Very good from what I've seen on the demo, and apparently it works on Linux however it's only available in .EXE format; I will download it later when I've time though and test it out fully. If it does work on Linux, and I can get it working, I wouldn't mind using that.
Basically, I've used plenty. I must say, the best I've found so far is SSM. Looks wise when you first install it isn't the best, but it's very easy to customise and in the end I had it looking like my site. IF it worked with Mozilla I'd have kept it; in fact, if it weren't beta and worked with Mozilla then I'd even pay for it - It's a great help desk, and is exactly what I'm looking for in a help desk.