Just to add to what has been said, I got the profile sander over the summer to finish off some crown moulding I had milled for some renovations in my home. It was particularly valuable during the installation of the moulding for creating seamless joints, as my plaster walls were very uneven and made it almost impossible to get the ends flush on two long pieces. , even with a scarf joint. After that project, I figured I wouldn't have that much use for it unless I were doing another large run of moulding (which I had not immediate plans to do), so I returned it and put the proceeds towards a Domino -- it does it what it does really well, but not much else.
And of course, I recently got a commission to do a large room that called for almost 400 ft. of moulding. So I promptly repurchased the LS 130, knowing that it's a lifesaver in these situations, especially when you make the moulding yourself, and it is now a permanent part of my tool kit.
I especially like the versatility of the profiles. They are soft enough that you can form them into the shape of the profile with a little pressure. And as others have already mentioned, the DIY profile kit will help you sand those shapes not already covered in the standard profiles (particularly smaller bull-nose shapes). Be aware, though, that there is a size constraint for the DIY profile -- I haven't worked it out exactly, but if the profile has tiny elements, like beading, you won't be able to sand one element discreetly without inadvertently sanding down another.
My only complaint is the sometimes inefficient use of the sandpaper, though I'm not sure if there's any better solution that would still maintain the full dust collection capabilities of the sander. For many profiles you end up using only one part of the paper, because it's riding on the edge. Once that edge is used up, you can't reposition the paper too far unless you want to sacrifice dust collection, as the holes on the paper will no longer line up with the profile.