I want to implement something here that would deal with all sorts of requests (tech support or business processes that we don't currently have a system for) and allow them to be filtered and assigned to particular users. I'm looking at 2 different products:

Zendesk
SysAID

They both look to do what I want and seem quite configurable, anyone got any views? This is primarily for intranet usage although some tasks might be assigned to users outside the organisation. 25 users at the moment, I think it'll be 30 before the end of next year