Probably not going to get a consensus here, especially since there's lots of good options.
I use a forcefield sub 4. It's thick, so you need the right size suit. However, after having a minor highside (is that a thing?) and hitting my lower back when I was only wearing an insert, I decided I wasn't going to play that game again.
As anecdotal evidence, I had a much more significant high side after I got the new protector. While I had a concussion, broken wrist, and such, I didn't so much as have any soreness on my torso (wore the forcefield chest protector too). Doctor was surprised.
Link:
https://www.revzilla.com/motorcycle/forcefield-back-protector-pro-sub-4
If interested, I'd reach out to TJ from riders discount.