You could spend double your budget , and still not end up with something as reliable or accurate as the AA Guns you have already had.
A Daystate Harrier or X2 may fall into that budget range , and are very good , if a bit 'dated'.
If you were after something a little different and a good solid 'all rounder', I would say A BSA Scorpion SE , in 177 flavor would be just what you could be looking for.