I currently use both Prime and NovAqua. I have no apparent problems with either.
I use the NovAqua when medicating (other conditioners, which contain hydrosulfites, can interfere with some medications), and for doing small water changes in small tanks (see below).
Prime is pretty cheap, too. My 250mL bottle (I think it was $4.95, online) will treat 2500 gallons. Roughly 200 25% water changes with a 55g tank.
However, as you might guess from those numbers, Prime is quite concentrated (which is the second reason I keep a small bottle of NovAqua around). Most dechlorinators that I've found are dosed at 1t (5 mL) per 10 gallons. Prime is dosed at 1t per 50 gallons. So, if your water change is less than about 10 gallons, it can be tough to measure out Prime. It is safe to somewhat overdose Prime, though.