The wife uses a White's IDX pro. That's the only detector she has ever used, and based on her hunting success (she out-detects me as often as not) I doubt she'll ever want to change. In the years she has used her IDX I have used a Tesoro, an XLT, a Sovereign Elite, a V3i, and a couple different pulse machines. The Tesoro was the only one in the same price range as her IDX (I think it was an Eldorado (??).
If you buy a used machine you can find a good value. I would recommend you get a non-motion function on the detector for pinpointing (not essential, but a big help sometimes) and get a machine that uses a lighter power supply source (i.e., 9V or AA batteries instead of C or D cells). Your back will thank you for that. Troy, Garrett, Whites, Tesoro, Minelab, Fisher...stick with a name brand machine you probably won't go wrong. And just to be on the safe side (my personal preference) I'd buy a Whites machine (no, I don't think they are necessarily superior to any of the other comparable machines) because of the way White's Electronics supports its customers with very reasonable charges and fast turnarounds for repairs. You could buy an XLT, or QXT, or Classic, or IDX in fair condition quite reasonably - and know that if something wasn't quite right, Whites would repair the machine - and make it like a new one in function - for a very reasonable amount of money.. 'nuff said.