Well - I have a shutter (got second hand) and its a very nice marker. BUT, nd this is a very big but - it has a new reg. and a new barrel. THe shutter is basically the Spyder TL with a reg / expansion chamber. However, the reg and barrel are both crappy and you would soon want to upgrade them, thus wasting the extra money spent on the shutter.
So I would recommend that if you want to get a high end blowback, get a more stock one so you're not wasting money upgrading average parts (Ie you can upgrade crappy parts).
I also agree with jeevusmax. that you must set a price limit for yourself. I think you would be better off with a stock cocker if you can afford it as you will find yourself constantly wanting to upgrade stuff on a marker. So it would be better to be upgrading a cocker than a spyder as cockers are basically better (IMHO, don't start a bloomin' spyders are as good as cockers war here)
Thats just my opinion, but if you get a spyder, first upgrade should be a new barrel then a new reg, whereas for a cocker I would get a new barrel then maybe a new bolt.
Thankyou and goodnight,
Tom