I had Ace 250, deepest dime to ID correctly was 4", with AT Pro I got dime with correct visual & tone ID at 7". This should make your chances of finding older coins much better. I really don't think the Safari is worth $400 more. The Safari is 5.5 lbs, the AT Pro just over 3 lbs.
The AT Pro beeps solid high tone on a dime in air test to 10". The Safari will beep solidly on a dime in air test to 11.5" with just occasional correct high tone (mostly low & mid tones). You could buy a used Safari under $700 & then if you didn't like it, no big loss. $998.95 new Those who really learn the expensive Minelabs do great but would think most at first dig much trash.
The AT Pro can go underwater to 10', with most gold rings found in waist-deep water. The MAP (minimum advertiseable price) on the AT Pro is $595 but some dealers will go somewhat lower in phone or e-mail quote. I've seen used ones as low as $375, but you would want to be sure you got the latest camlocks version or older one that's updated with camlocks. Best wishes, George (MN)