I have the "E" size multifix on my 11" lathe. I made a new stud (no T slot on my compound). I also had to skim the bottom of all the tool holders to get 3/4" tools down to center height. It was a bit of a trick to get the small chamfer worked out, but with that sorted, the result has been awesome. I'm glad I went with the "E" size as I like using the 3/4" tools. One feature that I like with the 40 position is that I rarely need to loosen or swing the tool post.
I have a CXA on my 15" lathe, it is also good. I find I end up adjusting the position of the tool post on nearly every job. The diamond tool holder needs a different angle to tune and face than regular perpendicular tools. Another example is chamfers right off the tool edge. All that said, I am not going to replace the CXA with a multifix style.