What's the United Joint? Is it interchangeable with others or just with theirs?
The United Joint is basically a 5/16-14 but is an improvement. I bought an EC7 dark stained curly maple with the Ex Pro shaft upgrade. I always really wanted to use the Ex Pro on my Schon's and possibly on a custom Leon Sly I have. I say "improvement" because you can really feel the last few turns tighten even though the pilot is smaller than the beefy pilot my cues originally have. Very secure feeling.
For a while, I was debating about getting the Ex Pro changed to radial to use my other cues. (Mezz has no interest in making that shaft for other joints, I've asked.

The Exceed cues might be great but it seems very difficult to actually get one. I do not want to wait 18 months for a catalog cue. The CP13SW models look tempting to me but "composite" wood scares me off.