The fans are 420 mm (~ 4") variable speed (76-101 cfm) computer fans. I haven't had any trouble with noise, but I mounted rubber gaskets between the fans and the wood. They also came with brass fan covers that look really nice. I bought them from an online computer hardware retailer for like $12 per fan.
Yes, light escapes from the fan holes, but the fan blades are a clear blue plastic which adds a cool effect.
Yes, one fan sucks and the other blows (Literally.). I am very happy with these fans. I've had no problems with them at all.