haha once you get to that stage of a baja, it's closer to a sandrail with a bug body on it.
a camber compensator is exactly what its name implies. it compensates for camber during steering.
if you know how the swing axle geometry works, when you go into a turn and lean, you get REALLY nasty positive camber. a camber compensator is a big peice of spring steel that bolts to the bottom of the transaxle, with bushings that push UP against the axles. a brand new compensator, will hold the cars wheels at 0 camber even when you jack up the back of the car. It does increase the stiffness a bit, but the trade off is a MUCH nicer feeling car during cornering. no matter how fast you go it will always stay extremely level during turns with very minimal body roll. I suppose the closest comparison would be the leaf spring suspension on a corvette. where it's a single spring leaf mounted transversely (is that the right word?) under the car.
http://www.jcwhitney.com/CAMBER-COMPENSATOR/GP_2005946_N_111+10201+600003418_10101.jcw
best money to spend on a stock street bug imo.
you'd also be surprised at how many people prefer the swing axles over the irs for many reasons. one is that the swing axles are WAY more widly available, since only the later pans had them. to convert a pan to use IRS you have to hack that section off. Also, for drag racing, the swing axles are a lot stronger. there's only one joint, and that's at the transmission itself, so it's basically like running a solid axle. the KISS concept wins in that sense. but for baja and off road, yeah, IRS is best unless you're building a very mild baja where you can get away with having the swing axles.