I can confirm that the Larry tyre is much better on normal loose terrain than the endomorph, it steers more accurately in corners and doesn't wander in the same way on muddy loose and hard pack. The endomorph is however better in soft but not muddy stuff and of course sandy terrain, all imho of course.
I agree with Coast kid on the weight thing, my Jones is not the lightest thing on the plant especially with my hardcore build, but it doesn't ride heavy.
I've also found using a normal 2.25inx26 tube drops the weight significantly (not surprising really) and as yet I've had no issues, Jeff uses 99g super light 26 tubes, I'm not brave enough for that!