2L has some MQA files you can download free of charge to play with. They are accompanied by various source files, most of which are in relatively exotic formats. However there is one track that is available both in the original as-recorded 44.1/16 and in an MQA version. That means that now you can compare undecoded MQA with RedBook (I felt the MQA had the edge), and as soon as you have an MQA-capable device you can decode it and hear THAT difference.
I have an Explorer2 and when I asked Meridian about a firmware upgrade earlier this week (MQA wasn’t finalised when they released the product originally, and the release version is slightly different apparently), they said that it was going to be ready soon - so I hope we are talking about a couple of weeks away in terms of being able to get it.