Version 4 as it is the last in a line and well regarded. You must make sure it has the input output cards you require, or may require in the future.
That's it.
Earlier versions may not so easily be upgraded as Meridian have moved on and the costs may not be viable when compared to just buying pre owned what you require.
Version 4's that have been traded in with Meridian for version 6 cannot be traded again if an offer is made in future, so are a dead end and should be priced accordingly. Still great equipment though and I wish I had more spare cash to indulge.
Just my observations, good luck, Chris
