Which V brakes - does it even matter?

OK I may finally ditch the cantilever brakes on my rockhopper and go with the super modern (ha) V brake. I see a number of people using sifferent models around here - are there really any bad choices among cheap sets? Shimano and Tektro can be had for under $20 a pair. I'm just skeptical that there is any difference in quality at this price point and will probably go with whatever is on sale!