Power and spin are directly related, because the harder the serve, the more spin is necessary to keep the ball in-bounds. Generally, teams should have an aggressive serving strategy. This does not mean trying to get an ace every time, but serving to make reception difficult for the opponents. All players should realize, however, that they need to serve a bit less aggressively when you are losing 23-21. Serving floaters is a good strategy for many teams.
Floaters are easy to serve, but very difficult to pass.
The typical error with a floater is not floating, whereas the usual error for a jump serve is a service error.