I recently switched from six year old Resounds to new Beltone's, both at a cost of around $4,800.00. The new Beltones supposedly sample at a higher rate making them "better". I had a lengthy discussion with the audiologist about the lack of control (consumer adjustments), with the aids. The answer I got, that is what we're paid to do.
Another audiologist explained that while the extensive test they do allows them to shape the response curve to the hearing loss, the ear canal can and does change the curve, and they have no way of measuring that.
It seems most give hearing aids provide a low/mid/high tone control. When I tried to find out what frequencies these are centered at, no one knew or it is "top secrete classified information".
My take is this. The difference between the six year old Resounds and the new Beltones, minimal. Definitely not worth the price tag. Until hearing aid companies provide a multi-band parametric adjustment, users are pretty much stuck with less than ultimate improvements. I understand that to the layperson, this would be a means of messing the sound all up, but how hard is it to add a "return to home" button.
I wear them when I listen to music (and they do provide a huge improvement), or when am around people, but I find the lack of being able to fine tune them to my liking to be very frustrating, and I would image others feel the same way.