I slapped Prop-O-Drev on last year when we antifouled. It was OK for about 9 months, and as it's an aerosol it would be easy enough to slap a second coat on mid season during a lift and scrub.
As I said, it was an aerosol product I bought in Shamrock Chandlery last year. I had previously cleaned and polished/sanded the props, rudders, shafts and P brackets. The P brackets and rudders were primed and painted with normal a/f, but I primed and sprayed the props with the stuff. From memory, it cost about £25-30 or so for the paint, but the primer was more expensive (but would only need doing once, if you keep on top of it). Seemed OK, but I should have recoated after 6 months, I guess.
Propspeed is a very impressive product. A friend of mine had it put onto his props and shafts two seasons ago. All that was required was a pressure wash and props and shafts as clean as a whistle!. On that basis I have had it applied this season to my boat. I have it from others that they have had excellent results. It is a two pack product and requires careful application, but well worth the effort by all accounts