I have and have had a number of Pono's. I had an older Concert and Tenor and still have a Soprano and Baritone. I also have 2 Pro Classic Tenors. The 2 Pro Classics are of very recent vintage, both have cedar tops. I briefly had a spruce topped tenor of recent vintage.
The particular spruce topped tenor in my opinion was slightly quieter and not as resonant as the cedar topped instruments. Probably just the particular tenors. Of the two cedar topped ones, one I had Andrew pick out and the other I got on ebay second hand. The one I got on ebay came from a seller who told me he just didn't bond with the instrument. As it turns out I did bond with it.
I also own two Ko'olaus, one is cedar/rosewood and one is cedar/mahogany. The Ko'olaus are made of higher graded wood, and the Ko'olaus, while each different have higher quality appointments and details. The Ko'olau neck is still thick and t he Ko'olau's are heavier than most of my ukes. The Pono necks are thicker still and they are even heavier. That said, the two Pono Pro Classics play and sound like the Custom Ko'olaus. I don't think I could tell them apart in a blind test. They are that good, but keep in mind they are (a) recent, (b) Pro Classic models and (c) Tenors.
The other Ponos that I have now that are not from the Pro classic line, in my opinion are overbuilt. They are all competent. Sound is decent and the intonation is OK but not on a par with the Pro Classic Tenors. I can't speak to more recent Ponos that are not Pro Classic Tenors.
The Ponos are different from the so-called K brands, but so are the Ko'olau customs that I have. There are differences between Kanilea, Koaloha and Kamaka, but when I compare their Koa instruments there are a lot of similarities. Each has a somewhat different sound and feel, but in my opinion all three of those are far more like each other than they are like Ko'olau.
To me what is cool about the Pro Classic line is that for under $1000 you can get a tenor that is 95% of what you would get if you paid three or four times as much for a custom. You can have a Cedar or Spruce top, slot head headstock, gloss finish, great sound and playability. You'll get a great instrument for slightly more if you get an entry level Koaloha or Kamaka or Kanilea. If you are someone who gigs or who travels with their instrument, who doesn't want to put their high end custom in harms way but you want a great looking and playing instrument that is replaceable and not horrifically expensive, then the Pono Pro Classic line is just a great working musician's instrument.
I do think the Ponos Pro Classics have gotten better and better. Both of the ones that I own are impeccable. The book matching is flawless. The finish is neither too thick nor too thin. Everything is aligned. I've looked at some older ones and the book matching was not well done, the finish was too thick and unevenly applied, and little things were "off". I have a Ko'olau spruce/mahogany that was built in 2006 when John Kitakis was still building and I have a Pono cedar/mahogany from 2014, and it would be easy to convince me that they were built by the same person. They even have a similar sound and feel.
So yes, Pono cedar/mahogany, the one I have is wonderful. The Ponos have been continuously improving. They are unique, if you want a small body, thin neck or light weight, you won't get that with a Pono. All of those things are things I have liked in ukes that I've owned so I would swear that Pono is not for me, except that I love the Pro Classic tenors. I consider them to be great workhorses.