The best sunscreens, of course, are ones that you will use! It makes no difference whether you're using a spray or lotion- whichever you feel more comfortable with when it touches your skin. One of the problems we've had with getting patients to use sunscreen is that not all formulations are particularly elegant and may feel sticky or greasy on the skin. If you prefer lotion, use that- if not, use a spray.
Finding an SPF of 30 or higher is our current recommendation from the American Academy of Dermatology. With an SPF 30 or higher, it is usually easier to obtain in a physical blocker, which means a sunscreen that contains zinc or titanium. I have a small preference for zinc over titanium, so one that contains zinc oxide would be my first choice.