My DAW experience
 

I've had a lot of bad luck with DAWs and VC...

I tried FL Studio....its ugly...really ugly...kinds like a fisher-price audio workstation. The midi timing is awful...luckily I did get VC working with it. The workflow is awful....for me anyway.

Sonar....nice fat program...not phat...faaaat...bloated, etc. I did manage after about 100 tries to record something from VC...it was full of glitches and timing errors.

Cubase....I did actually have the chance to see the loading screen of VC before it crashed....and kept on crashing.

I finally found Reaper, and it works flawlessly...oddly enough. Its small, fast, and portable.

So if you are at the end of your rope, consider giving it a try.

Couple things:

What OS version of VC are you using?

Do you have LIVE Mode activated when you are experiencing the lag issues?

I'm using Cubase Studio 5 on an old dell laptop w/o any problems, just curious as to if either of the above are to blame.

Im using the newest beta, 3.0.1.12...Cubase 4
...I can get some audio out of it...but cubase will not stay open for more than 45 min.

Running Cubase 5 (legit) on a new system, quadcore 4gbram XP, with 3.0.1.06. I have no issues with VC, and stability has been great. If I alt tab too often/change windows back and forth, I find it can start to get bit slow and or choppy, but that seems reasonable enough. Running Cubase only it works perfectly, for hours at a time.

FL can actually be extremely fast, if you know your way around it.. I prefer it for quickly getting ideas/grooves down, then moving into a more advanced DAW (Cubase) for working on arrangements and refining the track. Just takes time and practise, like all software.