My only complaint about the BLU is that the screen seems much less reflective than the FLU. Presumably this has something to do with letting more light through from the backlight. However... it also means (IMHO) that the BLU is next to useless without the backlight... it's practically unreadable except under the very brightest lighting conditions. (ie direct sunlight)
The FLU, on the other hand, has an amazingly reflective screen that looks great under any halfway decent light source.
So with the light, the BLU wins for image quality hands down. But... if the light ever breaks, the FLU will still be usable but the BLU will not be.
Edit: On some further reading, it appears this is caused by the BLU using a screen with a yellow tint, many people have replaced it with a glass screen and reported inproved colours/brightness. Something I might have to look into...