Ok, I am all about PvP, I did not play through the SP missions and only did like 4 COOP missions taken together on the both titles.
Negative:
* No anti cheat. That was actually the worst part with the game. I was GRAW2 moderator at TWL for a time and it was sometimes kind of hard to be cheerful when people started to bicker about SS tis or dat.
*No SADS at release, they came later but some of the community where already gone then.
*Game Spy did turn some people off. These days the third party system is common, criticism was perhaps to harsh.
Positive:
Well the game in itself was not that bad, not at all. I reinstalled it the recent week after OPDR showed what a let-down it was. Cod MW2 seems to go the same way, less unexpected though.
And GRAW2 had in its haydays not much fewer players than ARMA2 has now. Perhaps GRAW2 wasn't such a PvP on-line disgrace after all.
When it comes to actual ingame stuff I must say that I liked the sound in GRAW/2. Some parts were made unrealistic due to underestimation of the players knowledge. But most of it was the best I have heard in any game.