eSupport is one of the most feature packed support systems; in this tour you will find why over a thousand companies have decided to opt for eSupport and use it to process their daily support requests.
Kayako is by far the best help desk solution i have tried. Fast, affordable, and a lot more features than perldesk. Very good multiple employee support. The only disappointment is no ability to "take ownership" of a ticket and no indicators that show which tickets you personally have replied to.
The newest version of Esupport is the best we have seen. The features blow PerlDesk out of that water! We have been with Kayako for over a year now, and have been very satisfied. It provides a level of professionalism that is very high. Integrated with ModenBill, the two work great!