Lately there were great improvements in Cycles, but I have not yet seen very great character animations on technical side. For you Cycles is ready for animations? Or is it better stick on Blender Render (I am not sure it is the right choice for future)? What do you think about other renderers (Vray,3Delight,Yafaray, Octane, etc…)?
Cycles is designed for animation, but I’d say that without deformation motion blur it’s not quite there for character animation. Vector blur works, this is true, but it’s messy and will be unnecessary to mess with in the long run. Deformations are set to be handled in this years GSoC though, so that’s good news. We’ll see how it progresses. Another big point I’d say needs to be touched on for character animations is the SSS shader. It still has a lot of room for speedups, and desperately needs them IMO. A single layer isn’t too bad, but going into multilayer skin setups means hours upon hours of render time at HD resolutions even for a single character. These are the two big hurdles to clear in my mind for character work, after that general speedups to BVH, hair, etc. code will just be icing on the cake.
Ok, thank you for the info. I guess we have to wait further two or three official builds. I also hope for some speed-up on not progressive sampling so we can use it as default choice 
Have you used it recently? It got some serious speedups a while ago, and in my personal tests (at least for simpler scenes) the speed is now on par with Arnold for noise free images. I’m also working on a tutorial series for Blender Cookie that shows how to properly diagnose noise and use the non-progressive integrator.
Happy for recent improvements, I will test surely. I run and search the Blender Cookie tutorials.
On a related topic with Cycles, I’d like to ask: could anyone give some general advice on how to optimize video rendering times with Cycles?
I recently read an article by Andrew Price on optimizing rendering time for an image, which I found very helpful, but are there any ways at all in Cycles to make consequential frames render faster than the first one? (got a hint on that with the buffering options for render in Cycles, although I’m not sure those options work that way…)