I have a 6-yr-old Sony XGA projector that rarely used at home. After trying Wii at my friend's place on a TV, I am convinced that projector is the way to go for Wii since you need a lot of room for movement. I got my Wii set up the first time yesterday. At first, I used the standard sensor bar to see whether it works good enough before I opened the Nyko wireless one. I had problem in positioning the wired sensor bar and a sensitivity issue. After an hour, I switched to the wireless one. I observed big improvement in sensitivity and the stability of the pointer. We had a lot of fun playing tennis and bowling in our family room yesterday with a ~60" projection and standing ~10ft away. My hands are all tired right now.
I don't see any problem with the wireless sensor bar. If you are using a projector or large screen projection TV, the wireless sensor bar is highly recommended. I paid $18.09 for it including tax.