Depends a little on what you will use it for, but I have had a lot of different PCPs over the years, Rapids, Falcons, Steyrs HW100's, daystate Air Ranger, AA Pro Target, AA NJR 100, AAEV2, AA400x 3, AAMPR400 x4 and a few that I have forgotten.

But, for your budget AA400 every time. There is no gun that is more accurate than a 400 no matter what you pay for it. I should know I own two Steyrs which are fabulous, but no more accurate than any of the three 400's or four MPR 400's I have shot with. I can shoot just as accurately with my AA MPR 400 as I can with my Steyrs or Air Arms EV2.

They are cheap for parts, easy to repair and simple to work on if you are mechanically minded. I have shot a few S200's and the are nice with a great barrel, but not as nice as a good 400 in my opinion.