Any person who has ever wanted to see the G-boys in a yaoi, this is about as close as you will legitimately get. Many of the drawings Reku Fuyunagi has created of Heero and the others makes them seem even feminine than usual. Yes, this is possible. When I read it in middle school I found myself extremely uncomfortable. This was while I was still shedding my ignorant homophobic shell. Now, of coarse, I'd kill to get into Quatre's bed.
Plot wise, it is interesting. It's about how the pilots, especially Heero, deal with life in a now weapon free world. It's the age old question, "what do soldiers do when the war ends." It's extremely thought provoking. You also get to see a little affection between Heero and Relena, no, not Duo sadly...
Ground Zero does not provide you with any amazing mobile suit battles. However, if you are a fan of the anime or, rather, just the characters in general, you'll enjoy seeing them in a new situation, and acting rather silly at points. Basically, it's worth picking up but don't get your hopes up.