Comments about 'Keystone' for internal ticketing

We have been using Jitterbug for a while for our ticketing system - but have quickly outgrown it - and seem to have a need to move onward to a SQL based set-up - I've been looking at a few and have started focussing on Keystone - anyone using it and have some comments good/bad/creative re: same... please hit me off-list... -- I am nothing if not net-Q! - ras@poppa.thick.net