Depends on your definition of "better".
The Thiele will have more low-end and sound bigger. Both will be tight, but the Rec slant will be tighter. Either way, you'll want the cab on the ground or it will have no low-end at all.
Stacking a slant cab on a Thiele sounds GREAT.
As an alternative, I have a 1x12 closed-back ported cab that I think sounds much bigger than the Thiele. It gives my 2x12 recto vertical cab a run for its money. Huge.