I have been flying a DG 101G for three seasons and absolutely love it.
-No bad habits in the air or on the ground
-excellent rudder and aileron authority even at very low speeds. High wing clearance makes crosswind TO's/Landings that much easier
-GC hook for towline will be intimidating on your first tow but is a non-issue
-light wings with easy spar-pin assembly
-auto hookup elevator
-you can assemble this glider in 5-minutes if you have a good trailer (not including taping etc)
-comfortable cockpit with amazing visibility
-Elevator control mechanism greatly reduces turbulence induced osscillations
-trim is set with pull of pinky finger-amazing!
-cool looking glider
-tough gelcoat!!!
-climbs very well.
-soft wings very comfortable at high speeds
-linear and powerful single pane airbrakes

cons:

-DG tax to get parts (roughly $400 a year plus the part you are buying)
-canopy window could have been placed better
-Doesn't run that well above 80 kts...but how often are you cruising at this speed?
-must set trim full forward (Part of TO checklist) for aerotow; if you don't the glider will balloon quickly off the ground and get dangerous fast (especially light pilots)
-There are only 9 registered DG 100's in the USA. So, we can't all have one

I'm not aware of any problem areas? Check that the few required AD's have been complied with and noted in the logbook. Otherwise, buy it! You won't regret it.