I've had them for over 15 years. I tried the behind the ear type but I can't keep them on. I was forever knocking them loose, taking sunglasses on and off, pulling a sweater over my head, etc. I had to stick with the in the ear type, however, I believe the behind the ear give better results.
They are not a cure all like glasses. You don't put them on an have 20/20 hearing. You will still struggle in loud noisy situation like restaurants, etc. You can lessen that by choosing to sit with back to wall instead of middle of floor. Overall I am much more comfortable wearing them than not.
When I first got mine I realized I had not been hearing sounds like crickets chirping, or rain falling in the woods.
Mine are Phonaks from my local Doctor.