Ive owned my AT Pro for two years now, and absolutely love it.
Never used any other detector minus the ACE 350 I started with... The Pro's learning curve was just steep enough to keep me intrigued but still allowed great finds on day one of use...
I run the 5x8" coil on mine 99.9% of the time, and it excels here in the soil of the Texas Hill Country.
The way I look at it, it doesn't matter what brand/model/or cost of unit you commit to, if you don't take the time to learn it your gonna have to embrace the suck. This includes research, location, and utilization of common sense.
I suppose the $5-600 bucks for an AT Pro just means it pays for itself quicker! I offset the cost of mine in the first three trips, within a week. No one here detects, so to learn the VDI and audio I hit sports fields and found 73 dollars in quarters, and gold and silver jewelry galore... And I hate jewelry and clad! But it was great for familiarization.
To each their own, but the AT Pro is a machine I can't foresee myself ever needing to upgrade from.