FWIW, I'm very happy with my Truetrac. I have a Daily Driver with a NP242 and want to keep the fulltime option available. If you have a 231, you can use a Full Detroit without affecting driveability. An ARB is a good option also, and IIRC they make a HD carrier that uses HD shafts (someone slap me if I'm SPOBI)
With that being said, if money is no object, I'd pony up the cash for the ARB.