I wanted to chime in, because I have been through several LMS implementations, and I have consulted to help companies find the best LMS for their needs.
Invariably, poor fit comes from one source- the purchasing company not defining it's requirements deeply enough before seeing vendor options. The company really needs to define exactly what they need the LMS to do and then ask the vendor to SHOW how it is done in the system.
Why SHOW? Simple. If asked "can your system do X?" the answer is almost invariably "Yes", because it is almost always possible (technically speaking). HOW the task is done varies significantly platform to platform. In some it's a click or two. Others, it's additional tools (ka-ching!) and others it is a process that takes code and processes that would make a NASA Engineer's head spin...
So, I encourage ANYONE looking for an LMS:
1. Document your needs explicitly - as clear as possible- AND GET DETAILED - "can update courses" isn't enough, you have to break out all options (can update a course while retaining completion/progress, can update a course requiring all users retake to re-certify.... etc...)
2. Privately (do not disclose to vendors) determine priority requirements. Your list will be long. Clearly define your "must haves" vs your "really want to have" vs "would be nice, but we can live without"... This not only ensures vendors fulfill core criteria, but is a quick way to evaluate viable options (it doesn't matter who hits most requirements if one of your must haves is missed, so eval those first).
The reason you don't disclose to vendors- the response will be skewed to put your top priorities in the best light. You get more of an honest response if they see all requirements as equal.
3. Send the list to vendors and request they SHOW how these requirements are fulfilled. Each as a line item taking no more than a few mins.
Litmus test 1: If they balk at the time it will take, they are not serious about your business.
Litmus test 2: if any line item (i.e. ability to update a course without losing progress) can't be demonstrated in under 3 mins for any core requirement.... it is a potential sign of a BAD fit.
The major benefit to this, is some stakeholders (CEOs, Auditors, Tech folks) only need to review a few things (reporting, security, etc...) So instead of holding them hostage in meetings for a full vendor preso, they can get a short set of videos of 15-20m each of what they NEED to review. It optimizes their time. Further, it stops them from commenting on things that aren't their area (I cannot tell you how many times roundtables with C-suite folks had C-suite people comment on user UI and skew the selection- they are NOT the end-users!)
Anyhow, you get the point. It's "company defines needs, vendor addresses". Focus. No spin. Rules defined. Stakeholders aligned.
I have an Excel spreadsheet available to gather and rank requirements as well as put in ratings. Once the spreadsheet has all that data, it can render charts, ratings, etc... to provide a shortlist of what vendors to consider.