Welcome to the forum LuckyRon...
Minelab denote their detectors in a numerical fashion...therefore the 3000 is the later unit Lucky Ron.
If you are starting out, and only can buy one of those, i'd advise the 3000, but the 2000 is still a very capable machine. (It was also the first commercial PI detector that turned detecting upside down)
Good luck in your new hobby/interest...
Cheers
Gypsy