You won't lose any airflow unless you mount 3 2.5 ton truck winches on top of each other in front of your grille and fill in the gaps with foam sealant.
A 8274 isn't going to disrupt your airflow enough to make any kind of difference. By the time the air gets to the radiator, its back to laminar flow. Also you've got a fan that helps out a lot.
From what I've seen, the plain Warn M8000 is about the best for a Jeep (CJ, YJ, TJ). They are cheap, relatively fast and reliable. Bottom line, they just plain work. I will tell you that line speed is actually something you want. Many winches out there are slow and this can cause issues, especially when performing a full pull.
As for load draw, I wouldn't worry about it. I've got a Warn M12000 and YOU KNOW that sucker pulls some juice. I try to turn off most of my electrics, set the engine at 2500 RPM and then winch. Then I make sure not to shut off for about 5 minutes after the pull. If you do that with ANY winch, you won't have any power issues. With modern vehicles putting out 100 amps (or whatever) at idle and more than that at higher RPM, you shouldn't have an issue if you also turn off radio, wipers, lights, A/C, etc.
I haven't seen them in action but I'm hearing good things about Smittybilt (sp?). I haven't seen a darn good thing about Milemarker electric winches.