I'm running RTW with SP2, and I've not had a crash after about 100 hours of play. The only problem I've had was with the demo interferring with MP, but removing the demo and reinstallking RTW sorted that out.

I've played a couple of MP games with acceptable lag, at 2v2. I haven't had a chance to try 3v3 yet.

I think they have put out a good product, and provided the MP patch very quickly.