I think the 3 inch tube is the perfect do everything well length. For the purposes of the discussion in this thread, I think it solves the problem(s) that those who would otherwise carry a 4 inch gun, encounter with the 2.5 and 2 inch guns.
The only problem I ever had with a 2.5 inch Combat Magnum was a tendency for the grip to angle out away from the body and the revolver to flop around on the belt when using certain holsters. Sadly when using a belt slide holster - which I prefer - it happened often. The 3 inch tubes don't do this.
With the 3 inch you also have the advantages of full length ejection of spent casings and the very slight - often overstated

- velocity increase of the slightly longer tube.
Laurent - I am green with envy at your 3 inch MR 73 !!!

Possibly the finest revolver ever made. By anyone. Is yours ex French police? I'd love to shoot one and dream of owning one. Very nice indeed sir!

Regards 18DAI