I have the Sennheiser Whatever-45. The smaller of the two available. They are 100 times better than the plug in the ear Telex. However, they only take the edge off the noise, I wish they did a little more. As for the the other model up, the -25, most of the guys that have them keep one cup off their ear so they can hear. Kind of a waste if you are going to use them just like the old headset.
I flew with a guy that had the new Bose Aviation X. I tried them and the were a lot quieter and very comfortable. I don't see myself tossing a $500 headset on the shelf to shell out a grand for the Bose.
You can payroll deduct the Sennheisers.