So far, I love Blender.
So, anyway I decided to force myself to learn the Blender UI, the UI itself is not so great or as intuitive as you may think, but once you find what you're looking for its easier to find it next time you need it.
From a programmer's perspective, the program feels made by programmers for programmers,for example you don't "Freeze" transformations, you instead "apply" rotations, translations and scales, which makes sense when you realize that programatically, what its done behind the scenes is to apply a transformation matrix.
The armatures system for animation is great, I think it DOES beat the one in XSI in most aspects, for example you can use and manipulate individual bone envelopes to set influences, which you can't in XSI, there you apply an envelope for the whole rig and then you weight paint the problem areas, which usually are not a few.
You can also move, scale and rotate an armature and the mesh it deforms independently in object mode without it causing annoying side effects later like when you realize you had your mesh object rotated 90 degrees relative to your skeleton and then to fix it you have to re-envelope your mesh, which, if you had to do too much weight painting to fix, you'll have to do again.
But right now the reason I am rejoicing on Blender is the Python API, its a bit rough, true, but when you manage to rewrite an exporter that gave you nightmares for (still ongoing) months in 2 weeks without any mayor pitfalls, I can only say "BRAVO!", in contrast, my exported animations from XSI refuse to work properly.
And of course is always good to know that if you find yourself in need of a feature or find a problem with the software, you can go and fix it yourself. [smile]