In the approximately 10 years I have been shooting LF, other than the Boss screen, I think I have tried most of the available ground glass options, including the original that came in my Wisner Expedition, the Beattie Intenscreen and most recently the Satin Snow. For one reason or another I found each of them lacking. (I would have to say however, that in terms of value for the money the Satin Snow is quite good.)
A few weeks ago I purchased a Maxwell screen. I was hesitant for quite a while on this purchase because it is quite expensive. But eventually I decided to bite the bullet and go for it.
Prior to last week, I haven't had time for any photography since I installed the Maxwell screen and was anxious to try it out. I just returned from a 7-day road trip of camping and photographing, travelling first to the mountains of West Virginia, then across over into Virginia, driving the entire length of the Blue Ridge Parkway down to North Carolina with several side trips along the way.
With respect to the Maxwell screen, all I can say is, "Wow!" This screen is, by a wide margin, the best ground glass option that I have tried. The off-axis viewing is much better than I expected and much better than anything I have previously used, with very little light fall-off in the corners. For the first time, using a 6x Silvestri loupe, I was able to stop down to f/32 and check focus right up into the corners and actually see something. The screen is so bright it was as if an LCD had been installed in my camera.
Needless to say, I love the Maxwell screen and am quite confident I have purchased my last groung glass/fresnel option. Yes, it is expensive; but for me, at least, it is very much worth every penny.