Thought I'd add my 2 cents worth... for my driving style, both on & off road, I prefer the swingaxle rear suspension.
Main reason... simplicity.
A swingaxle system consists of an axle on each side & an axle bearing on each side.
The IRS is much more complicated. It has an axle on each side, a total of 4 CV joints & boots, a CV flange on each side of the IRS transaxle & a CV stub axle on each side in the trailing arm, plus the stub axle bearings on each side. However, if you break an axle or CV joint, it is easier to replace them or remove it altogether for flat towing.
The IRS supposedly rides better, but I feel my swingaxle rides pretty well too. I've been everywhere the buggies with IRS have been & vice versa!
A swingaxle pan can be modified with the IRS pivot mounts or a IRS pan can be run swingaxle!
Tire air pressures are very important on a f/g buggy too. I run 10psi all the time in P235/70R15s mounted on 8" wide rims & on the front, it depends on which set of tires/rims I have on... anywhere from 8 psi to about 12 psi.
So it all comes down to personal preference!