I think a lot depends on the make you go for matey....
If buying a budget brand winch I would go over the top on single line pull figure...
There are some 12000lb ones on ebay for around £200ish...
I think the branded ones like Warn, Superwinch, Goodwinch, Ramsey etc tend to put up with a bit more...
My yella fronterror has a Warn m8000 on it and I have abused the pants off it...killed 3 lots of solenoids, but the winch is still going strong...
I should add this winch has dragged the fronterror when dead, with all the extra weight of its cage 33's etc (and me

) up the cliffs which is not far off vertical before...granted with a snatch to get more wire off the drum, hence lowering gearing, and the snatch doubling the pull...
I bought a spare m8000 as it came up at the right price for bits for it, but it never broke, so that will be the rear winch on the chevybravafing as will tuck in the frame nicely...
I would go new, not secondhand (as they will be knackered), and get the most powerful that the budget will stretch to...best bet might be to check out Pedro's when he gets it fitted, and then see if his seller will do a repeat sale for the same price...