LIPOS are definitely better, but if you have not gotten this fact yet, then you have not been reading through the RCM threads enough. Then again the best reference any of us can depend on is our own experiences with the R/C products that are available to us. Get yourself a good Lipo pack and let us know how that works out for you.
Lipo is the single most important thing to happen to electric. Brushless is a close second, but IMO without lipo, brushless looses much of its shine.
even brushed motors benefit from lipo. all of my crawlers run lipo, and a few use brushed motors. Huge difference over nimh, especially when startup power is compared!