There are a lot of competing products.The IMS-LD specification is very large and has many different options. Each product can implement the most suitable features. Also, it does not indicate how to implement it. And therefore, different LMS can implement it in a different way depending on their services. This is a compatibility problem, but it can be solved by a convenient mapping between the different IMS-LD references and the different services of a LMS

Moreover, when writing the specification we tried to incorporate the ideas from the competing products (each one of them has its own way of dealing with the IMS-LD specification), and from the experience we had when using them. A detailed analysis would be too much for the moment.