My audiologist allowed me a trial test period < 2 weeks to test drive proposed new hearing aids for me. I do not remember the brand name, but they were top end audio amplifiers. I was surprised and disappointed how much audio feedback occurred. (squeals, chirps etc) in noisy environments. Especially on subway trains, buses, or outdoors with wind. Cup you hand over the hearing aids in the office. Do you hear feedback? Software, no matter how great, cannot control the physics of microphone+speaker squeal. Those audio limitations may be ok with some people. After some research, I learned of a new type of hearing aid, EarLens, that uses a mechanical hammer to tap on the ear drum. The audio feedback is mostly gone and the frequency range of what can be heard is greatly increased. Of course, price is a factor in the personal decision process.