I've got a ford 9" installed in mine... Can't say that its cheaper or easier than the 8.8 lol. I went with it because it was unique (kind of)... And i've had years of experience with them. 8.8 disc brake brackets bolt right on to the ford 9" and having the ability to pull the 3rd member out is pretty sweet. This allows me to have a 4.56 setup with my detroit and a 4.56 setup with a full spool.
It's kind of a personal preference decision. The 8.8 is incredibly strong, affordable, and easy to swap. The d44 is a great swap as well as the ford 9"...
Pros Ford 8.8:
Availability, price, disc brakes, ease of install, decent aftermarket, matching lug pattern
Cons Ford 8.8:
Aftermarket not as good as ford 9" (but still strong enough), "everybody's doin it", c-clips (kinda)
Pros Dana 44:
Probably alittle tougher than the 8.8 (debatable), maintaining chrysler (dana) parts, relatively unique.
Cons Dana 44:
hard to find, no disc brakes, lower aftermarket support, pricy, hard to find
Pros Ford 9":
Dana 60-like strength, removable 3rd member, easy gearing, HUGE aftermarket support, unique, easy disc brake conversion, matching lug pattern
Cons Ford 9":
Cheap but hard to find, relatively pricy to build, relatively low pinion on carrier, much more involved to build.
Those are probably the easiest axles from my experience to swap into a jeep. Once you get on up the the Dana60 range then you would probably already be answering these questions yourself.
naturally everything I just wrote is up for debate, I certainly don't claim one is better than the other and I dont claim to have covered everything in the above list... Again it is a matter of personal preference.
Good luck axle hunting!