I think it is at least decent composite. But, a good video transmitter will set you back at least a hundred bucks or more. The better ones will cost more and then you really will start going... "Why didn't I just wire this?" The loss in quality is definitely an issue, but I think the bigger issue is the requirement for power.

You can't run a projector without power, nor speakers, so it just makes sense to do things right and spend a couple of weekends doing it right.

NOTE: I have seen a pair of rechargeable speakers - batteries built in, wireless. They were definitely nifty, but also had very limited volume capability, range, and sound quality. It was acceptable for their use, since they were being used on a patio in an rental. So, the owner could leave them on the charger, then just bring them outside when they wanted to sit on the deck. But, that is about the best true wireless speaker setup that I have seen and it is a long way off from the Onkyo HT-770 system in quality, yet ended up costing about as much for the 2 speakers as the complete Onkyo system does. Ouch.