I think you can't go wrong with either one. I don't have a KoAloha, but I have a friend who does, and her tenor sounds amazing. It is very loud and has a great tone to it. I have a Kamaka tenor that is my prized possession, it isn't as loud or powerful sounding as her KoAloha, but it has a sweeter tone to it.
In terms of style, the KoAlohas are very mod. The Sceptre, the Sunday, the Jukulele, all have nontraditional looks to them - even the headstock and bridges of most "regular" KoAlohas are cutting edge (the crown bridge, etc.). They seem to be on the forefront of a lot of technology and design. One note: from what I have seen, the KoAlohas are very favored by people who are deeply religious, and I believe I have read that the Okamis used religious symbolism in designing some of the parts. If you are religious, that may lean you toward them, if you are not, it may sway you in the opposite direction.
i think that Kamakas are the absolute opposite of KoAlohas (again, this is just my two cents). They are not flashy at all, very traditional looking, with often just a satin finish on the koa. Although mine is curly, and I have seen a few curly ones, most of them tend to have pretty straight grain koa wood. The thing with Kamaka is that they have not deviated a lot from the traditional style, which fits a company that has been making their ukes since 1916. They are the "granddaddy" of Hawaiian ukuleles, and a lot of their cache is based on the reputation behind their name and legend.
A good compromise might be a Kanile'a. (I don't mean to hijack you in another direction and feel free to disregard this thought). My friend with the KoAloha and I both have Kanile'a tenors. She plays her Kanile'a 99.9% of the time, almost never playing the KoAloha. In the interests of full disclosure, I play my Kamaka 99.9% of the time. Kanile'a has a great TRU bracing system that allows it to be pretty much the same volume as the KoAloha, and their ukuleles can have a sweet tone similar to a Kamaka. They also walk the middle line in terms of style, with both traditional and modern touches. And their UV finish is terrific.
That being said, all of this gets thrown out the window when you consider that while these are great companies that make great products, still, each ukulele is individual unto itself. Which means, if you can play them in person you can better judge the sound and style you like the best. Failing that, I would try to find as many sound samples (through YouTube or elsewhere) of the KoAloha and Kamaka to better determine which is the best for you.
Sorry, I'm not familiar with Maui Music ukes. And again, this was all just my two cents...