+ 1 for the DTS, it's by far the nicest sander of the 3. Well, that's my humble opinion anyway. The DTS feels really nice in your hand because of the shape of the pad, and allows you to sand along edges and get into corners.
The LS on the other hand is a bit of a one trick pony to me. The linear action is nice when you need it, like when you do profiles, and that's what it's for, but when you compare it to an orbital motion it lacks both in smoothness and aggressiveness. Never make the mistake to think you can place the LS and the RTS in the same category because they have the same pad. They act very differently.
As for the RTS ..... well, meh... I'm not a big fan. Because of the small pad it has a bit too much of a tendency to tip over sideways when I work with it, and with such a nice delta pad for the DTS as alternative, mine gets very little use. I only use it when no other sander will fit the workpiece.
Sandpaper is also a concern. With the RTS and LS you're almost entirely dependent on Festool paper. Not that that's so bad, it's very good stuff and reasonably priced when you consider how long it lasts. But as for the delta iron shape, that's a very popular format over here and shared with a number of sanders from other brands like Rupes, Metabo, Milwaukee and Bosch, so there's a wide range of papers available from other manufacturers as well.
but I have 20 (or was that 200) other tools on my list that is also in the "need this tool" category unfortunately.
