And I'm not just talking about the HUGE amount of bugs in it.
Seems like we're forgetting that BF2 was barely playable 'til the 1.3 patch, and even then kept spitting people out without so much as a by-your-leave.
That said, BF:BC2 isn't without its crashes. I've had one from the single player and one in multi player when I alt-tabbed out during a map reset. That'll be two crashes in three days. Not great batting, but neither were terrible problems; the single player check point system meant I only lost around two minutes of play and the multi player crash was totally ignorable as I just joined straight back into the game. YMMV.
The rest I've experienced have been classic lag/synchronisation issues. I've warped back into a building that I'd just left all of once so far and had one or two choppy moments where my target was warping in front of me, but both of those occurred on the same server at a point of apparently high lag. Don't think there's anything to see there.
Aside from that, not experienced any significant issues.
The single player was short and sweet. Entirely linear and with a couple of irritating sections where, if you did it right first time, it'd feel like you were totally awesome. I didn't, and so they felt fairly fragmented. With the possible exception of the cliff top race through the snow in the jeep, where I flung myself off a cliff one time but redoing it was actually pretty cool as second time through I got it just right. My biggest criticism of the single player is not its length but its derivative nature. Occasionally felt a bit like I was playing sequences from other games. Still, it was entertaining and well humoured so I forgive it for that.
I've not got a huge multi player experience so far (~3-4 hours) but what I've played so far is fairly encouraging. There's all the same lone-wolfing that I remember from BF2 but with a "Do you want to join a squad?" tick box on loading into the server people are often automatically ending up in groups even if that grouping is fairly nominal. That said, helping your squad gives more points than helping your team (e.g. squad heal = 20 points; team heal = 10 points), so you're encouraged to stick with them.
Spawning is now on any squad member, but squads are limited to 4-man. I say "but", but actually I think this is a good thing. 4-man is relatively natural and supports numbers from 2 to 8 very well, albeit split across two squads in certain configurations. What this means, though, is that clan members are naturally split across a wider play field and, thus far, this has left me with less of a sensation of clan-stacking.
The first unlock weapons in Assault (XM8 Prototype) and Medic (M249 SAW) both feel very worthwhile and a good step up from the fairly flimsy starting weapons. That said, once I gotten used to the starter weapons I felt they were effective all the same; not quite the killing power or stability over range that I wanted but still just fine for killing people dead.
The unlock system has similarities with BF2142 in that med-kits, shock paddles, ammo boxes and so on are all earned as rewards not provided as part of your initial load out. For a new player I can see this as being a massive boon as it means that they've had to play the "just shoot people" game for a while before they get confusing role stuff thrown at them. For the hardcore, like us, it's just a hurdle to get over before we can do the stuff we always used to be able to. I've got the basics for both Medic and Assault already, and working on the repair tool for the Engineer. Once I've got those, I'll probably do something basic with the Scout (the only other class I've not mentioned) but I suspect I'll concentrate on the Medic.
Grenades seem to be in less plentiful supply. Assault class gets its noob-tube, but only two grenades (unless he's sat next to his own ammo box). Just as with BF2, the grenades need to arm though I think I've been killed at point blank by physical impact. Hand grenades are given out as one per person and their throwing arc seems to be less insane than other games. Also, a grenade warning indicator and an auto-shout of "grenade!" gives away the incoming frags so a mobile person can often avoid the spam. There doesn't appear to be any way to cook grenades either. Result? Less of the Counter-Strike and COD grenade spam, though still plenty of it.
Snipers are still as irritating as ever but fortunately not very effective when it comes to actually, y'know, winning. I have been shot once or twice at point blank by a semi-auto rifle but mostly me+SAW versus sniper means a bloody sniper mess and me tea-bagging his corpse, or something.
Destructible environments help keep things interesting. Sniper in a building being irritating? Blow out the walls (which is a lot of what 40mm grenades are used for). Still a problem? Level enough fire on the building to bring it down entirely. Tends to mean that defenders are working with a steadily reducing quantity of cover, but actually that works well. Keeps it fresh, keeps people mobile.
Vehicles play decently well versus soldiers in that they're destructive but not totally dominating. That said, I stepped into a Bradley on one map and was 13 for 0 at the end so it's possible that they're overpowered (though I was absolutely slaying, so maybe I was just in the zone too). The miniguns on the Blackhawks are a bit crap, though. Surely they should mince meat people on touching them? Hmm, maybe I'm playing the wrong game if I'm worrying about that sort of realism...
All in all, I've acquired a fondness for BF:BC2. I can't speak for longevity, though destructible environments do help in that regard, and the levelling/unlocks system is rewarding but not too speedy.
Comparison to BF2? There's no commander role. The commander was a fundamental part of BF2. That disjoint makes a comparison fairly nonsensical. This is a game better compared to CoD4. In that regard, it fairs favourably. CoD4 might be a little more fluid but that makes it more like Counter-Strike than anything else. As a game, I think I prefer BF:BC2 for making things just a bit more dirty, less clean cut and generally having a sensation that, as a new player, I'm not constantly being pwned by air strikes and helos called in by the kids that can put a 40 hour week in practising the game.