I first bought a hollis neotek semidry, and then a seaskin drysuit. I dive in northern Japan, where the water ranges from about 10 C (50 f) in the late spring when we start diving, up to about 23 C (73 f) in the peak of summer. It would be possible for me to use the semidry for this entire range, but honestly it wouldn't be comfortable. Down to about 17 C (62 f) the semidry works well, but you do need to mitigate cooling on the surface interval, it's a PITA to get into, and the second dive is going to feel significantly colder. IMO semidry's work better for one long dive. Also, the compression is extremely noticeable. When you start the dive you feel super buoyant, and unless you overweight yourself descending is a struggle (I usually swim down the first few meters). After about 5-10 meters of depth, the suit compresses and suddenly you feel like you're descending like a rock! It was shocking for me to experience the first time.
Shortly after I bought my semidry, I ended up buying my seaskin compressed neoprene drysuit. It cost me about 300 dollars more than the semidry, but I like it more. by changing what I wear underneath, I can dive all year around with it here, and actually be comfortable in all conditions. You also don't need to spend a huge amount on undergarments like some people say. I bought the seaskin 150 g undergarments for the coldest temperatures, but above that I either use a bare exoskin (basically their version of lavacore/sharkskin) or just thin wool base layers in the warmest conditions. The buoyancy characteristics are also much easier to work with, because the suit itself doesn't change buoyancy, you just aim to maintain a constant volume of air in the suit, and vent when you ascend.
I also think that in really hot conditions, having 8 mm of neoprene on and waiting to dive is awful. By comparison a drysuit is thinner and doesn't bother me as much.