I have one of each. My Kamaka is a tenor strung with low g (Fremont blacklines). My Kanile'a is a K2 tenor strung high g with Worth CT strings, and my KoAloha is a Pineapple Sunday currently strung with Worth BL strings.
It is not a straight comparison for me because the Pineapple Sunday is not like a regular tenor (it has a brighter tone and actually I find the body shape a lot less easy to play). But I have played a KoAloha tenor in the past so I will try to give you my advice based on that ukulele.
Each has its strengths and weaknesses.
I think the KoAloha probably has the best tone of the three. It has great volume, and their ukuleles sound amazing. If their strengths are in design, where I would consider it lacking is perhaps in the visual arena. This is just my opinion, and mine alone, but aesthetically I'm not crazy about some of their bridge styles. I don't care for the bowtie bridge currently being used on their tenors, and that has been a huge factor in keeping my from buying one. But if you can find one with the old crown bridge styling, snap it up. It will sound the best of the bunch. And their customer service is the best, hands down. All three have great families running the companies, but I think the Okamis are just that little bit nicer and have the better warranty over the Kamakas and the Souzas.
For aesthetics, I think the Kanile'as are the best. They use a unique UV finish that is simply stunning. They also have a bit of bling in a lot of their ukes. Major downside (at least for me) of the Kanile'a is the bridge pins. While I like the clean look of them, they make it a pain in the behind to change out your strings. And for someone like me, who is constantly trying out new sounds of strings, it is a major downside. Plus, as much as I love the Souzas, I think the KoAloha and the Kamaka's tone are better. But I think that might be my ukes. I hear that a lot of Kanile'as are touch and go...some sound amazing, others less so.
Finally, there is the Kamaka. For name and history, they can't be beat. There is a reason why they have been making ukuleles for almost 100 years. If you want a historical collector's piece of Hawaiian tradition, I think they are the one to choose. One downside of that many of their ukes being out there though is that they have a huge waitlist for repairs. Think about it, if Kamaka has 100 years of purchases, KoAloha 15 and Kanile'a less than 10, it makes sense there are more people in line for repairs. Another major downside is the crappy strings they put on their ukes. So when you try them side by side in a store, they will fail by comparison. I think you really need to hear a Kamaka with upgraded strings in order to really get the true tonal capabilities of their instruments.
In the end, you can't go wrong with any of them. Good luck and keep us posted on what you choose.