Lots of great info here and in similar threads.
After reading everything I could find and getting some great advice from members here, I bought a Pulsar xp30f thermal scanner. Imho it is an excellent choice if budget is a concern. Great design and function and it does exactly what I need, spot animals without having to run a spotlight and scare the game as well as show my location to people and animals. As far as performance, at 100yds I can see the difference between a rabbit and a cat, at 200 yds I can still see it but can't always tell the difference. At 300 yds I can tell a small deer from a coyote, at 400 yds not necessarily. If I lost mine, I would buy another in a heartbeat.
My current set up is, spot with the thermal and shoot with a scope mounted red light. This works pretty well for my hunting ( predators ). When I can afford it I would like a dedicated thermal scope as well, but if you can only have one I would definitely get the scanner.