My 2 cents worth
I own both models and have never had a single problem with the original black Pro Pointer.
I always liked the black on and still use it.
I originally purchased the Pro Pointer AT primarily because of it's being waterproof.
I have to say, after using both, I find the Orange, AT Model MUCH nicer all around and in my opinion it is a better performer, and simply more fun to use. It got quite an environmental beating this past season and is very rugged.
1. it's waterproof
2. it's a lot more sensitive than the original black one and offers 3 programmable sensitivity settings.
3. the one touch re-tune is nice (you don't have to turn it off/on like the black one). In fact, I find the one touch re-tune is so convenient it negates the need for having 3 sensitivity settings.
4. if you prefer silence, you can turn off the audio and use only vibrate while pinpointing.
5. the lanyard loop is a nice touch
6. I like the orange color because of it's high visibility.
7. it's rugged, has been very reliable, and never falses
Battery life seems about identical to the Original as far as I can tell.
I purchased my Pro Pointer AT model (the carrot) at the going rate when they first came out and haven't shopped for another since then so I can't comment on current prices/deals. I'm really happy that I upgraded.
There is also a Pro Pointer II which is an upgrade to the original black Pro Pointer but it's not waterproof and there are a fewer setting options.