best bet is to get down to a good pb shop and fiddle with a few guns or alternitivly ask a few people if you can try theirs down at your local site...ive never known anyone be refused a look at somones marker...99% of people are more than willing to talk guns with you if you ask, and all teams will have someone with them who can tell you what goes wrong with what.
end of the day there is no 'best' marker its all down to personal choice....ive been playing pb for over 10 years and i still look at every gun i can get my hands on...i use a cocker by the way, althou if i had a pot of cash im not sure what id buy...tho prob a bling bling e-blade cocker or a fancy impy