Have you been evaluated yet for a cochlear implant? If you have, you need to talk to your surgeon about the MRI compatibility of the 3 brands.
Also, I suggest you reach out to others with CIs (look for MedEl, Cochlear America and Advanced Bionics forums, FB groups, etc.) and ask them how they like their CIs.
As to the ringing (tinnitus), mine is less noticeable while wearing my CIs.