Since no one else has responded yet, here's some maybe useful info. First, I'm still in the process of setting up my projection system so I haven't actually seen any of these fabrics in action yet. However, I do have Pearlescent and M2500 samples that I'm looking at right now under a lamp. Here are some differences. I wish I knew how they would affect a projected image!
- very smooth, tiny specks of "silver", very white, not as reflective of lamp light like I thought it would be with 2.0 gain
- not as smooth, light texture, off white color, kind of silvery, very reflective of lamp light, appears to shine
Now that we know that M2500 is really 2.3 gain, I'm not sure Pearlescent is really 2.0 gain, because .3 gain should not appear as different as I'm seeing with lamp light! Of course, in a proper setup, it isn't direct near-field lamp light that is being reflected. Also, compared to DaLite High Power (2.8 gain) M2500 seems more reflective, too! The M2500 seems more like the DaLite Super WonderLite 2.5 gain.
Oh well, I guess I'm no good at judging this stuff from samples. I just looked at the Video Spectra 1.5 and it looks to be brighter than Pearlescent 2.0, too...
Paul, I suggest you order some M2500 samples from Draper. Sigh.