According to dev mailing list:
Show off your Matcaps, maybe someone will like it enough to include it, and even if not someone else will find it useful.
CC0 assets are the most flexible. Less restrictions means more people will use them.
matcaps works in older blender versions… I dont understand why need new build for it
It’s just easier this way. A single click verses all the set up from before.
Doing it the “hard way” though had its benefits. It’s especially cool to have two matcaps on the same object (diffuse and reflection) and so you can just adjust the mixing between them for different uses and effects.
Also, it’s faster than a full fledged material on the object.
a single click vs 3 clicks? ah, this is the blender forum I see…
faster? it works in single texture mode so it is the fastest
Endi, you understand that this was added by Ton himself right? So you’re in essence bitching about a feature that the head of the Blender foundation felt that Blender needed. You seriously need to get over your hatred of new features and workflow speedups. You have a very confusing “angry old man” complex with your disdain for any kind of progress. If you don’t like the way this forum and its users operate, then leave. You contribute nothing to any conversation other than troll-y remarks and unwanted snark. But, like a Stockholm Syndrome sufferer you keep coming back. Either don’t bitch and troll, or leave. Pick one, and stick to it.
I don’t think masking worked properly with the old matcap method, so, if masking shows up using the new matcap method it will be well worth the effort.
If this is actually faster than the old way to do matcaps, I’d say it is a welcome addition 
And that it’s easier than the old setup is also a plus.
As a offtopic side-note:
Not sure if Ton read that here. But I’m really grateful for the retina display support in the newest builds. That’s faster than some of the commercial apps I use.
Thanks so much! Love how crisp Blender looks now.
Masking does not work with new method, I’ll point it out to Ton.
Upside though is it does work with dyntopo, which the old method did not.
Maybe Ton reading this forum and making the noobs wants. 
The old method of matcaps reduced sculpting performance by 30-50%. What is the performance like with these new matcaps?
Unfortunately the same.
Exactly the same and it’s really bad IMO.
I got ~45fps sculpting in solid with dyna and ~2.55mio tris
With the material/texture matcap in textured view it drops to ~8fps
With the new matcap in solid view it drops to ~8fps
Any yeh, DS-off/VBO-on, r54134
Either way… that’s not really usable. You can’t sculpt a clean stroke with those frame rates.
Hmm,
I always had performance issues with matcaps, so I didn’t use them. Instead I just fiddle with the opengl lights, or use the display tools addon with the skin preset which works fine in most cases. Hopefully the performance issues will be ironed out.
do you use glsl or single texture mode?
in single texture mode you must set the texture to refl mode
Thanks arexma. That’s a real pity, so Endi/abc123 is right this is just a faster way of setting up matcaps (single click vs three clicks) with the added benefit that this works with dynamic topology while the older method does not.
maybe that is why blender has consitently been improved. you don’t have to use the new versions if you dont like the new features. some of us find them useful though