Sounds like a choice between two great instruments! I haven't played these specific models, but I have played Kala Elite concerts (and own one) and Pono mango pineapple tenors.
I would choose the Kala Elite for personal reasons, and here's why.
First, Kala's koa is great... they've gotten much better at grading their koa that they build with. Koa is also becoming more and more expensive wood these days.
Second, I love the quality of Kala's UV gloss. It's on par with what Kanile'a does, it's very protective, and I love the look.
Also, I prefer Kala's tone in their Elite instruments, which to me is louder and is brighter (has more treble). Pono's instruments to me have always sounded a bit more traditional, even their pineapple instruments. Their mango instruments also noticeably sound warmer than their acacia, too. Some people don't like that brighter tone though so it is all personal preference. Of course be aware that going from tenor to concert, you would be getting an instrument that is going to sound a lot more treble oriented no matter what, pretty much. So take all that with a grain of salt.
Next, being from California, I appreciate the opportunity to support a builder in my home state that is creating great American-made instruments, so that's another factor for Kala.
Also, I love Kala's wide fretboard and wide nut width. The Kala Elite concert I have is the easiest instrument I own to fingerpick with, just for me personally. The width works well for me in that regard, though to be fair, it's not as if it is that much wider than what Pono does.
Finally, I personally don't care for appointments on instruments. I prefer to see an instrument made with beautiful wood, and if there is not a spot of abalone or shells and if there is no binding and no rosettes, I'm a happy camper. Kala's design style speaks to me in other words.
Both great instruments though to be sure... Pono makes very high quality ukes! Just sharing my personal opinion, and I hope it's helpful.