Chain tax store vs private vs software

I’m trying to get my taxes done. I’m wondering how cost (charge) and benefits (doing taxes correctly, getting largest potential refund, negotiating lower penalties) compare between chain tax stores, private filers, software, etc.

In my case, I have past years to do for myself, a deceased relative to do for this year, and possibly estate taxes.

Any suggestions?

If you have to ask, the answer is that you need to retain a professional. Particularly if you have several years of back taxes you’re filing, which it sounds like you do.

There is no software that I know of for the estate tax, and I’d venture to guess that most of the chain tax preparers never deal with it.