I have an Opio Sapele Tenor (not selling it) and I think there were finish issues. Mine was a B Stock from Mim and it had spider cracks in the finish. It does not bother the sound of the instrument one bit. It also has the “dead” (not really) C string...and I still love it.
I also bought an Opio Acacia Concert (from rubykey, I believe!) which I also love. I sold my Pono Pro Classic Tenor to buy it.
My “sweet spot” would probably be a 16” scale instrument (Conner? Tenert?) but that is probably a silly thing to wish for. (Note: it turns out the Kamoa Grand Concert Just reviewed by Barry Mac has these measurements).
I don’t have...nor do I need...two Opio tenors to compare, but I do believe that the Sapele is a louder wood. I believe this enough that if a Opio Sapele Concert popped up in the UU marketplace for a good deal, I might very well bite the bullet and buy it.
And of course, a Koa Concert is on my to-buy list...but I’m working on paying off other debt right now (newer iPad Pro). At the Minnesota Ukulele Gathering last weekend, a local was selling their Opio Acacia Soprano, and that was REALLY nice, too. Such a non-soprano sound for a soprano. I had my S1 with me, and my Opio Concert...so I heard it.
At the same time, don’t hesitate to buy a new Acacia model of the Opio Tenor. I am sure that it is possible not to like the KoAloha sound...but it you do, they are all good.