I have the Haynes, and it has paid for itself. For general stuff it is more convenient that the FSM, which I also have. For example if you just want to know how to remove the heater box, the Haynes will put the info at your fingertips a lot faster than the FSM.
But as mentioned, the current Haynes covers far too many model years. If you can find an old used copy of the Haynes for just the YJ, snap that up. I've never seen one, but it should have less useless stuff to wade through.
Dodge did not build my Jeep.
1988 Wrangler,4.2L I-6, Howell EFI JP-1,CRT HEI Ign,AX15 ext slave conversion, Zone 2.5" lift + 1/2" booms, BFG 31 x 10.5, Bestop.