We use extremes and cisco's at a ratio of about 50:50, We have hundreds of extreme eithernet switches, have used from single L2 managed 100Mb/s switches upto 10Gb/s L3 blades from extreme (and cisco alike).
I can't say I have any issue with them, you will find it so easy to pick up the CLI interface <TabTab> and I'd say every command requires less typing than to perform the same actions on the cisco's.
On the reliability side, the older switches had a bug that seemed to stop new link-up's being detected after around a year of uptime, but that has been sorted in firmware updates quite a while back. Never have a problem with them.
Especially compared to the price of the cisco's you really cant fault extreme's.
//TrX
EDIT:
btw, what extreme kit are you looking at?
//TrX