I ride the mako 150 and have ridden the king. Here are some comments. I enjoy both but the 150 I use all the time. I am 105kg.
I have limited surf experience but these boards are excellent in bay slop and waves. In surf I have no reason to believe there are any issues but I have had limited experience. There are some short wave chop patterns where the usual smoothness of these boards is not present and you get more annoying chatter. This is rare and only in some wind conditions at my local beaches. On any longer period waves this is not the case.
Pop is limited but you can obviously boost of waves. In flat water they can still be fun but they are wave carve boards.
I like them best as twin tips but have tried the king in mutant mode as well. There are many different preferences amongst mako riders in terms stance and straps etc.
I would say the 150 feels like a 140 twin tip but with the characteristic mako feel. The king feels like a bigger board. Neither are great light wind boards. The rocker and curved edges and lack of buoyancy limit light wind performance. They are good in any wind above the threshold where they go upwind easily. When that happens they rocket upwind well. Very high winds is no problem.
Carving is exceptional on both boards but the 150 is more lively. The king feels more cruisy. You need a little extra front foot pressure for the mako a to work.maybe it is just me but if you are in mutant stance on the king with straps it feels like the weight distribution is too far back to me when riding into the waves but fine riding the waves. Strapless this is not problematic and you adjust the weight distribution automatically .
If you get a sweet spot with the kite highish and your weight on the kite a lot you ride on the concave edge it feels very smooth fast secure and pleasurable and easy on the legs.
They are a board design some people love and others don't see what the fuss is about. I would demo first if you can but you may need a few good hours to get the optimum feel.