We have 2 Blue and 1 yellow Nanoskin towel. We have had them over a year and they are still going strong. True you don't see the dirt that is being pulled off, but you can feel and even hear it coming off. Did a 2008 Evo last week. NEVER clayed and had overspray. My partner who was stand 10 feet away said "Are you sanding that thing." That's how it sounded. But after a couple of passes it was smooth as could be. I would go with the towel. Fold in in 4's and it will last you a long time. We can clay a medium car in no time at all. I use ONR for the lube. Cheap and works great.
Just make sure to hang it when you are done and don't set anything on it. We set a box of gloves on one on accident and I still can't get all the carboard that is stuck in it off. The back will stick to velcro so put a piece of velcro someplace and just stick it. Also it's very sensitive to heat. If the car is too hot it leaves a sticky residue behind.