If you know what type of hunting you want to do that can help narrow things down. But chances are you'll try several types before you settle down on a primary type of hunt. Also take into consideration, and be brutally honest here, how much time will you have to detect? It doesn't make sense to spend $1200 on a machine you'll only use one or two times a year. On the other hand if you'll be out everyday, spend the extra bucks.
All the big brands have great machines. Though after having had machines from several brands, I find I prefer Tesoro...I love the simplicity of not having a display and I know the sounds well enough that I get a ton of information from just the sounds. My second preferred brand is White's. I've never really like Garrett machines. Don't be afraid to go used. You could get two gently, or never, used machines for what you'd spend on one new unit.
...but yeah, get a Tesoro.
