Thanks cmoses for the detailed writeup of your testing, the information really helps me to understand the background brighting you were describing.
Viewing Angles:
That makes sense that viewing at an angle would brighten the background, if there was already a bit of brightness present. The better the monitor is able to handle different viewing angles, the less you will notice the brighting of the background. So I would imagine on an IPS monitor there would be no difference.
One of test LCDs (Samsung 17") has a small bit of background brightness, and isn't good at all with angles. I leaned it back about thirty degrees this morning, and I could see the increase you described from your testing.
PNP:
I think the monitor identification is related to two ID pins that are usually shown NC (not connected) in VGA wiring specifications, but are used by Windows for PNP. In my current design, those pins are not passed through the mini, so I'll need to take a look and see if wiring those pins restores the PNP ability of Windows to detect the monitor.
70Hz Refresh:
I should probably add to the instructions that the refresh rate should be 60hz for both 640x480 & 1024x768. The issue is the vsync signal, and it needs to have negative polarity. I've had good luck with 70hz for both modes on my equipment, but the implementation could vary across video drivers. 60hz will work across the board though.
However, I'm going to test out something today with custom modes. I'll experiement by cloning 1024x768 @ 75hz, and see how changes to sync polarity work with the mini.
Great though that you are enjoying how the mini SLG works with your setups now that you've found the monitor you want to use in your project. Looking forward to seeing the finished build, do you have a project thread here in the forums?
I was experimenting last night with my xbox 360 and a cheapie VGA cable adapter + mini SLG. Rtype classic looked great with scanlines on my 32" LCD TV. I never thought of using the mini this way, but some of my users have been hooking up classic consoles like the SNES to LCD TVs, so I thought I'd give it a try. I'm going to keep working on making the mini as compatible as I can with as much hardware as possible. I will be opening a sales thread over on Shumps shortly, and the user base over there leans more towards consoles & pcbs. No doubt I will learn a lot about all the varied upscaler hardware used by that crowd, so it should be interesting!