I should elaborate on my first post (posting when tired isn't the best time).
I would recommend the Makala Dolphin instead of the Makala MK-S. I would recommend getting any uke in this price range from MGM (Music Guy Mic). The ones I've played that were purchased from him sounded very good.
The Kala KA-S is a good uke for the money. It is a laminate uke though and not a solid body. I share this more so you are aware of what you are buying. A laminate uke isn't a bad uke. It will handle humidity changes better than a solid wood uke, will still sound nice, and will be durable for travel, camping, etc.
The Makala Dolphin ukes are also good, and are less expensive than the Kala KA-S. The Dolphin has a plastic body and a laminate wood top. These are surprisingly good ukes for the money! It will be durable, etc.
I've played both a Kala KA-S and a Makala Dolphin side by side. I have not played a Makala MK-S.
To be honest I didn't notice a huge difference between the KA-S and the Dolphin, but to myself and several others the Dolphin sounded a tad more bright and lively. So I would have to give a very very slight advantage to the Dolphin in terms of sound. The intonation was about the same on each. They felt the same in terms of playing (the necks feel the same, etc).
I see the choice as one of price and looks. Both will play similarly and sound just about the same. But you really can't go wrong with a Makala Dolphin.