Which LMS do you use and why?

I went through trials last year and ended up choosing Litmos.   I'm all about simple and the process to choose an LMS provider was simple as well. I "googled" LMS providers, of which there are MANY, and narrowed it down to 6 on a short list.  The BASIC criteria I used for the short list : 1)how many learners we had 2) Price 3) US support 4) Ease of use.  Then I assembled a team of 4 to attend webinars presnted by the LMS short list providers and we posed questions and watched their demo.  A few we called back for a "second interview webinar".  Litmos was the hands down favorite because it met all the criteria, ease of use, being THE most important.  We all figured it out without even needing a user guide.  Litmos is not as robust as some products that are out there but we didn't need a full talent management product and we didn't have time to stumble through an un-intuitive product.