M3s all the way. Nothing else is as versatile and that's what yer paying for with Newmans. Quality on any good, well-made frame of any variety is about the same all around, mesh is your preference, tension is your preference, bolt mesh v. panels also your preference as all of this is available on most any frame type.
The M3 can go wherever you choose to go with screen building, without modification, and if you choose to get rid of 'em they have an excellent resale value.
I think those EZs are neato with the low-tech installation and everyone likes something square to clamp onto on all four sides but you need to trust and rely on Shur-loc to build the panels just right for the tension/corner softening/final tension you're looking for and your mesh can withstand. To their credit, Shur-loc does this job quite admirably and it's what makes their products actually work I'd say. But, what happens when you change yer mind, want to try something new, find a production issue that demands a change in screen building or want to see what printing at 65 n/cm feels like? Now you have a pile of panels that are no longer optimal for your shop.
My trusty quiver of M3s have let me go all over the map with mesh and tension and give everything I was interested in a fair trial. Now, I run at such low tension that they seem like overkill but when I can bump up my 330s by 2 or 4 n/cm and enjoy a much tighter print run...well you can't make an adjustment like this on anything else out there.
If you want to buy one frame type/system and be done with it for the life of your business, M3 is probably the one.
And get a roller master.