The 314 model is gigantic. Almost everything, except the largest drums, will fit into the 312. The problem with the 314 is that it is so large that most djembes that won't fit into the 312 end up rattling around inside the 314. (There really should be a 315 model, but there isn't; the step up from the 312 to the 314 is too large.)
I've had problems in the past with the TKL bags separating at the seam where different cloth colors are joined with tape.
Also, the grommets for the drawstring will tear out pretty quickly. (There is no backing or reinforcement for them, at least not on the two bags I bought.) My recommendation would be to ignore the drawstring and not use it.

- TKL bag weak points
- DJ3XX-2.jpg (37.74 KiB) Viewed 161 times
Finally, the handle on the top is a nice touch, but I'm not convinced that it is such a good idea, because it puts the full weight of the drum on the zipper. It's a good quality sturdy zipper, but I would expect it to wear out over time from the strain. When I pick up the bag when it is standing on the floor, I usually grab one of the two webbing straps at the front, or pick it up by the shoulder straps, rather than using the handle on top of the lid.
Don't get me wrong, I'm not trying to suggest that this is a bad bag. I still have one of them, and it is still holding up. However, in terms of quality of materials, workmanship, and amount of padding, it can't compete with the Drumskull bags. I expect that the TKL bag will wear out much sooner.
The TKL bag is considerably cheaper though, and it would be my second choice if on a tight budget.
Michi.