Alright after some thinking and debate im going to attempt to get the AT Pro, but im going to have to find a deal from someone or something because I getting 300 bucks and I will sell the Ace 250 for 200 because its in good condition and I have the box for it still and a rain cover for it so yes now the only thing I need help with is finding someone who will sell me one for 500
My advice... sell some other stuff and save up about $350, and add that to the clad you find with your 250. You can find a used AT Pro for that price. Once you get your AT Pro (or other detector), then sell your Ace 250 on ebay or craigslist.
I found my AT Pro for $350 on craigslist like new in box, but it did not include headphones and that was another $50.
There is nothing wrong with the Ace 250, it's not a "piece of junk" as someone else stated. If you locate a cheap 11"x8.5" DD coil for it, it is very easy to identify bottle caps and it helps in trashy areas.
The pro is nicer because it's waterproof, and the tones are shorter and change in volume to provide depth... so you get a lot more information about where the target is and what it is without needing to watch the display.
I almost never use the display on my AT Pro, but on my Ace 350 I had to watch depth constantly to determine if an object was large or small, shallow or deep. That is all I meant by being painful to go back to... sort of like driving with one eye closed. The main reason I purchased the AT Pro is so that I could detect in the water (which I do about twice a week).
Definitely do not sell your only detector until you have a replacement... if you do that you may get discouraged, or make a hasty choice on a detector just to get another detector.
Hope this helps.