Tippmann A5, brilliant marker, completely bomb proof if kept in good condition and cleaned and maintained properly (like every marker though). Had one for my first marker and it was brilliant, shot straight consistent and could take a beating when you trip on a tree root and smash it into the floor! No electronic gubbins to worry about and no electronic hopper to purchase!
I have a DAM, and it looks the mutts nuts, it can be a bit finicky at times though and I have spent a fair while taking it apart to clean it up between games to be able to shoot it straight! Its not a fan of low grade paint thats for sure! Its also heavy compared to a supair marker so can be a bit fatiguing after a while (although a carry harness sorts that problem out!) Oh and also you will more than likely want to remote line it as you can't use the stock with a 4500 bottle!
Etek is also another great gat, have 2 mates with Eteks and they are really nice to shoot!
Also have you played much paintball before? As not sure you would want to spent £1000 on your first gun, spesh if you decide its not for u or can't be bothered!