I have a tenor from Kamaka, KoAloha and Kanilea. It is interesting that this came up because just yesterday I was comparing all three of them and contemplated doing a post focused on the differences between the three of them. Here is a photo of my three.
In order, I'd say this (mind you this is only discussing my three tenors, I fully understand that another instrument from the same manufacturer could be better or worse and this is entirely subjective):
Kamaka: This is the oldest manufacturer, and they have the history and name cache. Their instrument is actually the heaviest of three that I own weighing in at 1.25 lbs. (the Kanilea weighs 0.5 and the KoAloha an even 1lb). They have very classic looks, nothing as flashy as the KoAloha or Kanileas. You can often find some pretty grained wood in even a standard Kamaka, but they are very conservative looking: white fret dots, a straight tie bridge, mother of pearl tuners. As for customer service with them, I had one fantastic experience and one bad so for me anyway they are mixed -- though I haven't heard complaints from anyone else so I would say they are still good on average.
Kanilea: My Kanilea is kind of flashy, with lots of curl and abalone. But even their standard K1 models usually are quite pretty with the UV gloss that they use making them stand out. I would also rate their fit and finish far above the other two brands. Most of the Kanileas that I have played have been much more on the mellow side, and some of them have sounded more muted. Of my three, I would say it has the second best sound. It actually sounds better than my Kamaka but not as good as my KoAloha (more on that below). If there is one thing I don't care for, it is the tuners on this uke. They are not nearly as good as the ones on my other two, but that is purely subjective and others may disagree. One other thing that can be a hangup is the bridge pin style of bridge. On the one hand, it looks very clean and attractive (particularly when you replace the plastic black bridge pins that came with it - I subbed koa ones instead). They are, however, sometimes a pain to use when changing strings. It isn't a make or break it issue, but it is the one K of the three that uses them. As for customer service, I have had very good dealings with Joe and Kristen but I have never had a warranty or repair issue (unlike with Kamaka and KoAloha) so I can't say for sure as to their warranty/customer service. I've only had pleasantries and sales dealings and on those, they were quite warm and friendly.
KoAloha: I think that KoAloha definitely has the least conservative styling. They change their bridges frequently, and they are everything from the funky crown bridge (my favorite) to the rounded bowtie, or the new bridge that somewhat resembles Kamakas, only with the KoAloha branding on it. They also have the most outlandish headstock with the five points. I like it, but I can see where other people may have an issue with the aesthetics. If you like, or don't mind the looks though, they are the one to beat (in my opinion). I like the sounds of my Kamaka and Kanilea -- but my KoAloha blows them away. In volume, it is probably 30-40% louder. And tonally, it is much brighter and clearer than the other two. Not to say they they are muddy sounding, but the bell like tones of a KoAloha are wonderful. They use a very unique bracing system, and unique soundhole. Plus, the Okami family used to be in plastics and did some inventing. I'm not sure if that is why they have such loud, clear tonal quality but they do. And for customer service, they are unbeatable. For one thing, the warranty on the other two is only for the original purchaser. KoAloha's "Better than the Weather" warranty transfers to any future owner. In addition, their sense of aloha and ohana is unsurpassed or even rivaled elsewhere. You truly are part of a family with them. I had a fantastic experience when they installed a 5-0 pickup in my tenor -- they not only did it in a few hours, but they didn't even charge me. Additionally, I sent them a Pineapple Sunday with a flaw back in April and this week they emailed me to tell me that Papa is choosing the pick of the litter of new PS ukes for me to get in a couple of weeks. Tonally: they are wonderful. Warranty: they are wonderful. Customer service: they are wonderful. Looks/styling: they are a love it or hate it.
In summation (long post I know), you cannot go wrong with any of them. They are all wonderful companies and wonderful ukuleles. I love all three of mine. But I would be hard pressed to pick a favorite among them. If I could only keep one of my three it would either be my Kanilea or KoAloha. My Kanilea has the looks I like, and it has deep sentimental value to me. But my KoAloha sounds much better. All of this is subjective, and each company has its fanboys and fangirls. I'm sure you will love whichever one you choose. But if I had to vote on which to recommend that you purchase, it would be the KoAloha: for the tone, the volume, the warranty and the customer service, plus they are the least expensive of the three generally. Good luck to you in your purchase.