The Descender is exactly the same as the Turbo, but without the remote lever. Which is a bloody stupid idea frankly, get one with a remote- you might think it's easy to reach the lever, and it is, on a canal path… But at times when you'll actually want to use it in a hurry, your hands will be busy with not crashing.
If you do foolishly get the Descender, you can add the Turbo kit later, for about £70. And you will probably want to. The dropper without the remote just drove me mad, all the potential of a dropper post but without half of the actual usefulness. Still, if you can get a good price for a Descender it can still be economic to upgrade.
For the post itself, it's brilliant- tough, reliable… They do have a wee bit of play but nothing severe, some people hate that but I only notice it when I feel for it. I wasn't totally sold on the idea, like most people, but I wouldn't be without it now I've tried one. Mine's not needed any replacement parts, or even any noteworthy servicing but when it does, the bits are easy to find and the construction is simple, it's just a stick and a spring.