That's a good deal for sure. I guess was wanting to see what the full features of 14 are before going ahead. Probably no use for 13 since most of the unresolved issues are still apparent in that version.
On the other hand, the offer they're making for 13+14 is pretty much the same price as previous upgrade offers have been, and you get two versions for the buck. I doubt skipping 13 will bring you a significantly better deal. You'd also have 13 now to play with and see if it's any better for you than 12. Seems like most of the discussion in the forum is that 13 finally got it right, mostly.