I ran a co2 system for a season and just changed out to a compressor setup. I dont regret it. Nice thing is, if you get a leak, you just let the compressor do its job. With CO2 you're outta luck if you get a leak. It will still run, but eventually will bleed out.
My CO2 system worked great, no complaints. But, I liked not having to refill. Its kind of like the nitrous vs turbo debate.
As far as running on nitrous, just make sure you use an expansion chamber and a regulator. As well as make sure you have enough bottle.
For a track bike, to me there is no major problem with running off nitrous with the right parts.
Mine is setup to run on a compressor, but I can switch back to my CO2 setup in less than a minute if I lose a compressor.