Of course, being around for ages is a big advantage, just ask Microsoft. :-P

The learning curve may be the biggest hurdle for many. For me, it's the material system and the renderer. I've learned to use Firefly up to a certain degree, using D|S usually means that the image don't look good enough to me. This is different for other people of course. And then I use the cloth room and the morph brush a lot. 

On the other hand, there are things for which D|S is better. I'm happy having and using both of them. 

A ship in port is safe; but that is not what ships are built for.
Sail out to sea and do new things.
-"Amazing Grace" Hopper

Avatar image of me done by Chidori.