Ridden (and sold quite a few of) both, they’re both incredibly capable and you will have a great time on either.
Tyre clearance is definitely improved on the 2017 model, comes fitted with 2.25″ Maxxis on the back now and a 2.3 will go in no problem. That said, if you like really big tyres and/or still want mud clearance, there’s still more room in the back of the T-130.
For me it’s the T-129 all the way though. The T-130 is the popular model, and the one that wins all the magazine awards, but that’s largely because on the whole, people don’t like 29ers. If you already like 29ers (I do, sounds like you do too) then the T-129 is one of the best (if not the best for the price point certainly) out there. Whilst the T-130 has 10mm more travel (not a big deal) and is arguably slightly easier to flick round the really twisty stuff (but we’re probably clutching at straws here), the T-129 murders it when the trails open up!
Oh, and T-129’s are easier to get hold of cos the T-130’s sell out much faster every time Whyte have stock.