Unless you break a lot of parts, maintainence on a nitro is less than an electric. They really don't get as dirty as you may think; just fill the car up, start up the engine and you're ready to go. Once you're done, just take out the glow plug, put in a few drops of after run oil and then run it on the starter box for about 10-15 seconds, put the plug back in and you're done and ready for next race session. Depending on the type of air filter you have, you have to either clean it or replace the filter elements after about 8-10 races or so (about an hour of actual run time).
I have both an electric and a nitro sedan (both TC3's if it matters), and I have much more fun with the nitro. I give my nitro a thorough cleaning after every few races (i.e. cleaning and reoiling bearings, rebuilding shocks, etc, nothing you wouldn't need to do on an eletric car to stay competitive). Really any nitro car is essentially a good car, so first take a look at what car has parts readily available at your LHS, and make your decision based upon that. Some are easier to work on than others, and I prefer the Nitro TC3 because of it's simple but effective design, plus it has lots of 3rd party support. None the less good luck with your choice, I just hope you don't end up putting your electric on the back burner like me.