Kayako http://www.kayako.com/

My company use Kayako for their hosted support ticket and live chat solution.

We used their version 3 solution for over a year the service has failed many occasions, normally due to server load.

Once I was told that the MySQL backup process caused excess load on the server crashing it.

In early 2010 they announced a new version they were working on. Later that same year they released it.. but only for new customers.

They advertised that the V4 hosted package was on super Amazon EC2 based cloud computing systems which were ultra reliable and had loads of redundancy.

They promised and promised that they would release an automated upgrade script for hosted customers but it never appeared. Every time I spoke to them (which is only possible via live chat or email) I was told an ETA of 2 weeks... even months on.

Eventually I yelled at them enough that they agreed to manually upgrade my package to V4.

Upon logging in the following day I was appalled to find that many features from V3 were missing and the new features meant to replace them seemed half finished.

On top of that, within 8 hours of the new system going live, it was down... again... so much for it being cloud hosting.

The only reason it gets a 2nd star is because there is nothing else out there with this kind of feature set priced even remotely close to Kayako.