Welcome, mmolnar!
I'll just jump in here for a moment...I have the F70 and the AtPro...I use the F70 on the dirt, and the Pro in the water. They use the same batteries. New batteries start in the Pro, when it says they are "finished", I put those batteries in the 70 and get another 10 hrs out of them, so in this regard (and many others) they are a great team. I LOVE the DP tones of the 70! It is one quick broom for sweeping large expanses of ground...the Pro shines in the water of course...both have found me a lot of gold and silver...
I agree 100% with SteveO...it depends on how and what you like to hunt, your personality, location, and style..The F70 with the 11"dd, super light, fast and powerful..the Pro, well, its waterproof and will not miss gold...
Both would be considered "midrange" units, both great customer service ...excellent finds and posts on both forums...not gonna argue with results...I think this coming year I will default to gold and jewelry hunting, not so much for relics or deep silver, so again, its depending upon how and what you like to hunt..read a bunch of the Forums..you may have to go back a ways when we were all out hunting hard and not snowed in...both units are simple "turn on and go"...technical drawbacks to both, but acceptable...TID screen on the Pro is too small to see, and the 70 is not waterproof...they each have strengths that surpass the other, and keep a guy afield for the majority of the year. Good Luck!
Mud