I think most people substitute their mechanical fan for an electric fan.
Also, the protection of being inside the engine bay is why most fans are put there. That's just the way I see it, I'm sure some run pusher fans.
1995 YJ: 4.0, 700R4, 231 C/J case, TeraFlex SS SYE/CV shaft, 8.8 with 3.73 gears, 136 Amp Alternator, Trans Cooler, Pavement Ends Flip-top/H-T, 2'' BDS Suspension Lift, MORE 5/8' Greasables, Sony GT-210 Xplode Head.
Under the Knife! See the build thread: http://www.jeepforum.com/forum/f12/badaddetudes-build-project-hrp-602142/