I "upgraded" from an O3 MSF 500 to an Ri200 with front loading zip at the start of the year. Both are XL, but the Ri is much more flexible and comfortable to wear. It has miles more room around the shoulders (not hard really, the other one was nigh on skin tight) and shut downs are no problem at all. In fact I can nearly reach my left valve with my right arm (no use really, but an indication of flexibility).
I spent ages with Shaun getting all the tweaks sorted, especially the placement of the shoulder dump. That was my main issue with the MSF, as the shoulders were so tight, the dump valve was too far to the front. It was no real issue when using a BCD or single wing, but I had quite serious issues dumping gas when I switch went to a twinset.
The front zip is great, no problems getting in or out. There is a technique, but Shaun went through all that. It does take several goes to get the hang of the part of the zip which goes over the shoulder, but it easy once you get the hang of it.