I have a Telex Echelon 25XT with 25 db passive noise reduction. I love this headset for it's comfort, its reliability and it's noise reduction. A benefit to this design is the comfort gained from the thick, soft ear cup pads. Even though the fit might be snug, the foam and covering is so thick and soft that they do not get uncomfortable for me on 2 hour flights in the Kansas heat.
When I decide to finally buy an ANR headset (if the 25 XT ever wears out, I guess), I'll strongly consider the Telex Stratus 30XT or the Telex Stratus 50. Both use a combination of active and passive noise reduction. Also, in the unlikely event that the battery runs out, you'd still have 29 db passive noise reduction. Not bad!
Geoff