Which LMS do you use and why?

My employer has been using Kallidus for about 7 years now, I have to say, my experience with this system so far has been anything but straightforward.

Currently heading up a project to replace Kallidus with Absorb by Blatant. Inital testing has shown Absorb is a much more efficient and straightforward system. The customer service provided by the vendor we are dealing with is significantly better than that we have experienced with Kallidus.

I definitely have to agree with a previous poster; there isnt one LMS that is perfect for everyone. You need to take the time to scope out your requirements, and then test a number of systems to find the one that not only meets your requirements but it easy to use for both the Admin and the learner.