I have several Ponos and a KoAloha Opio tenor. I like both brands very much. They are comparable in that they are both made from all solid woods and that they are both launched by knowledgeable Hawaiian companies branching out to offer a more affordable product. To me, they are the one true upgrade from the entry level stuff and very close to what you get with instruments that cost a lot more, so I think you've narrowed down your search to two great choices. Can't really go wrong with either one, but here are a couple of thoughts on them.
I have measured all of my ukes and what I found is that my Pono AT has the exact same weight as my Opio tenor. Moreover, the neck profiles on the two are very similar, both perfectly round and definitely not thin. The difference might be larger in the concert or soprano size, bot not with the tenors I have from these two brands.
As for the sound, I would argue that a lot depends on the strings. KoAloha ukes come with Worth Clear fluorocarbon strings and they ring out like bells. Compared to that, the factory strings from Pono feel stiff and sound dull to me. This is a factor I wouldn't neglect when comparing demo videos. And it's an easy fix after all, since strings are relatively inexpensive and there are lots of different sets to dial in to a voice you like. Both have a rich and full sound, but the KoAloha might indeed sound a bit more open and louder right from the start.
On the other hand, I would have to say that I think Pono is a slightly better value overall, considering that they offer the same type of solid wood, but at a lesser price, with a smoother finish and the additional benefit of a truss rod to make sure your instrument will be playable for decades to come.
My two cents.