I fucking loved rush on BC2. The few rush games I played on BF3 (about 50 games) were awful. There's nothing wrong with the mode, the problem are the maps.
I actually enjoy infantry maps on conquest (Metro, Bazaar and Seine), but I despise then on rush. What a clusterfuck! It's just a meat grinder, if you push hard enough you'll flush defense from the mcom and now it's your turn to grind then. Most rush games I've played were on those maps unfortunately. Map rotation sucks.
As far as rush goes, BF3 maps are so inferior to BC2 that it's not even funny. I hope B2K and further DLCs fixes this, as I miss playing rush, we'll see.
For all Dice talk about how BF3 and Frostbyte was going to be awesome, I swear to God, if they just ported BC2 and BC1 maps to BF3 instead of creating new ones I would probably be a happier man.
Also, a couple days ago I played a defence Tehran rush game with Faceless and one or two other gaffers (including a gaffer on the opposing team) were the attackers couldn't get past the first base and the game lasted for almost 40 minutes. SMH.
As soon as the game ended, most of our team quit, and it was our turn to attack. The defenders now had a 2 man advantage over us. They all fucking quit as soon as we got the first mcom, the game had to reset because there was not enough players and we were awarded a loss on Battlelog for scaring everyone on the other team.