Two years ago I was looking for a new machine and narrowed the choice down to the AT Pro and F5. I got a good deal on the F5 and went with that, and never looked back. There were some things I liked about the AT Pro (mainly the waterproof feature) but there were some things that concerned me; for one, the display seemed a little small. Also, while the AT Pro is a bestseller, there were some comments from people who utterly despised it--not the case with the F5 as far as I saw.
Over the course of this year the F5 beat out my other two detectors (CZ-7A, mainly good for beach work which I didn't get to do much of this year, and Compadre wader modification, which I intend for lake work but have mostly used for tot lots). I got an NEL Hunter coil for the F5 in September and haven't had either of the other machines out since...and have had the Hunter off the F5 only once, to work a trashy area with a 5" sniper. I've developed a rapport with the F5 that I've never had with another machine. The arrangement and usage of knobs just makes so much sense to me...it seems I have so much control over settings and adjustments, without stacks and stacks of menus and such.