We purchased an Aquamatic Pool Cover about four years ago. Let me start by saying that it has done the job of keeping the kids safe. When the pool is covered, a 180 pound man can walk on it without creating a problem at all. Because it floats over the water, there isn't even a risk of an infant drowning in water sitting on top of the cover unless you have had a torrential rainstorm. It does the safety job well, and that is why we bought it. So keep that in mind when you read my complaints.
Even when it was brand new, it always seemed that there were too many folds in it. The installer -- who at that time was the only installer in Los Angeles certified by Aquamatic, although I believe there is another now -- said 'it will settle in.' Well, four years later it still has folds. I think they cut them too large, on the principle that if it is even half an inch too small it won't work, but if it is a bit too large it just has extra folds in it. A few folds are needed because if the water level is low, the cover should still rest on the surface, but it should do that (at a low water level) without folds. Extra folds would be OK but the folds trap water and grow mildew at a prodigious rate; more on mildew below. So my first piece of advice, if you buy one of these covers, is to insist that it is the right size and don't believe them when they tell you five or six inches of folds are normal. When the pool is low, it shouldn't have any folds at all. (Mine has at least 5 inches of unnecessary material.)
Don't buy this if a beautiful appearance is very important. They sell hard the attractiveness of it, but it turns ugly fast. The problem is that leaves stain it, and some kinds of mildew stain it (normal mildew can be easily removed with a pressure washer) and there is some white condensate buildup from hard water. Overall, it has a mottled look within a year or two. We pressure-washed it annually, and from a great distance it looks ok (we bought a pool-colored blue one), but up close it is mottled with leaf residue and other stains.
The hydraulic mechanism has functioned flawlessly for four years. I don't think the ropes are going to last much longer, but I am hoping to get another year out of them; at that point my youngest will be a strong enough swimmer to be safe.
When there is more than an inch of rain, it is not possible to open the cover without first removing most of the water. With a half inch of rain, you can usually open it by a somewhat tedious procedure where first you open it half way, let the water settle, open it a bit more, let the water settle (a bit of water runs through the mesh at one end with each of these actions) and keep doing this until there is so little water you can just open it the rest of the way, at which point all the water runs out. But with more than half an inch, and certainly at an inch, this procedure won't work -- the motor isn't strong enough to move that much water, and you have to pump it out. A submersible sump pump is needed. This is a pretty dreadful feature, however, because typically you are have an extension cord near a pool full of water, which even with a GFI should make you nervous, especially when you are tossing the sump pump out to the middle of the pool. Once you have pumped most of the water off it, the cover will open normally.
I had one other unexpected and irritating experience with Aquamatic. Aquamatic describes in great detail how extensive and terrific their warranty is. However, certain plastic parts are excluded in the fine print. One of these -- a plastic "stop" that prevents the cover from opening more than it is supposed to, broke after about 6 months. This is a plastic part about 1 inch by 3 inches by half an inch. If Home Depot sold it, it would cost under a dollar, but they asked for over $500 to install it. I'm pretty handy and said I could install it myself, which gave me the second shock -- they wanted $250 for the part! It turned out that was parts for both sides (two of these things) but they would sell me one, so I bought that and installed it myself in about 40 minutes. My advice is never to open it all the way, which avoids the cover end hitting the stop, which avoids breaking the stop. If I break another, I'm going to fashion a replacement out of something like an old cutting board -- this $125 each part is literally just a hunk of plastic with two holes drilled in it. Additional advice: if yours breaks, replace it yourself, and if you can't work a socket wrench, find someone who can and offer them a case of beer and a pool party (you have the pool, after all) to fix it for you. $500 buys a pretty nice pool party, after all.
By the way, the fact that the broken plastic stop clearly had a manufacturing defect (there was an air bubble inside where the plastic broke, the air bubble made it weaker than it should have been) didn't get me a free one, as it should have. I think this is a way to get an extra $500 every year or so out of buyers.