Screen size and the 32 Gb memory card are what matters, eh? Maybe I'm just pointing out the obvious, but it seems the more cost-effective solution would be buying a 32 gig micro sd card for your DINC - at half the cost of the TB itself - and calling it a day. When you also factor in having to plunk down an extra 40 - 60 bucks for the requisite extended battery, you'd definitely come out better on the other side.
For me, screen size and the included 32 GB sd card aren't even the TB's best specs versus the DINC's. More impressive, I think, are the FFC and faster browsing speed - feeling quicker than the DINC's even at just 3G (Can't personally speak to 4G - not available here). Other than those aspects, both devices feel and function fairly similarly in my lowly layperson's hands.
(Oh yeah, the TB's kickstand is kinda cool in a way I'd never expected: Hands-free video recording - with the aforementioned FFC, especially.)
So, I guess unless you've got a real bad case of screen envy and/or money to burn, stick with the DINC for now. Especially if you're happy with it. I had no complaints with mine - a smartphone first for me.