My school uses GW and all of the students think it is awful. Mind you few of them are computer science majors, nor am I, however many of the above comments are accurate regarding incompatibility with various devices.
I've been scouring the internet with queries on how to either install a GW client on my Mac or access it through Outlook for Mac. No luck yet. If either of these options exist in useable versions, their existence needs to be more obvious, as does the proper sequence for installing and using them.
The kicker? My school charges $40k per year, and we get the poor service from GW, but we STILL have to pay for iOS apps for email!