I have been looking into this a little, from a practical framing perspective. As previous posters have pointed out, the glazing itself will add a color cast to the print. Last weekend I overlaid swatches of TruVue Museum Glass (anti-reflective coated, 99% UV filtering, TruVue AR Reflection Free glass (anti-reflection coating, 78% UV filtering), and glass from a cheap mass-produced 8x10 frame on a print made on Exhibition Fiber. The Museum Glass added a brownish cast, the AR added a greenish cast, and the cheap glass added a greenish cast, but less than the AR (but the cheap glass was 2mm while the AR is 2.5mm). All of the brights looked dimmer under all of the glass, but to about the same degree. What I could not tell, because I didn't have a sample of known OBA-free paper was how much that effect is the result of the glass itself and how much is the result of UV blocking (I assume the plain glass blocks some UV, but do not know how much -- one web site said 25% blocking, the "International Ultraviolet Association" website said "Normal glass (as used in windows) is transparent to UV radiation up to a wavelength of about 330 nm (or UV-A light). The transparency is quite high so almost all UV-A light will pass through glass. Below 330 nm (UV-B and UV-C), almost 100% is block by normal glass". I took some photos that I will post eventually.
I personally prefer the color cast that the Museum Glass adds to that of the AR, but AR costs 3/4 as much as Musuem Glass, and is somewhat easier for me to cut because of the sizing. TruVue also makes an non-convservation glass, UltraVue (anti-reflective coating, 65% UV blocking) which is "white water" glass, so I assume it imparts less of a color cast -- but it only wholesales in lite sizes that are too large to be practial for me, so that's not an option for me.
I am contining my investigations. BTW, does anyone know if the Epson Hot Press is OBA free (I have a sheet of that lying around)?