I have been checking out the R12. I would assume the general character of the R10 would be the same on the basis that if the same engineer(s)/designer(s) developed both they would use the same approach, only scaling things so as not to tax the 10" driver.
I think this review includes a good discussion of the R12:
https://www.soundandvision.com/content/infinity-reference-r162-speaker-system
He describes the R12 as "a commendably subtle sub" and I think that is fair. If you want to impress your friends with lots of low end oomph, you'd want a sub that calls attention to itself. The R12 (and I'd bet the R10) blends seamlessly with the mains and it just seems like the mains have a ridiculous amount of bass for bookshelf speakers (with the R162's in my case). There is good solid bass for HT, but not like you'd get out of most of the subs recommended here (which run at least 3 times the price).
So my thought is it is a very good sub for music, but it will not induce the "sh!ts and giggles effect" of the serious kick-ass subs for HT. It will add a lot of solid bass for HT. This is specifically my perspective, but if I am just wanting to watch a movie for the entertainment of the show, a sub like the R12 is a great asset, but if I am wanting to experience the HT effects as a thrill (kind of like a rollercoaster ride),I want the sub that says "hey, hold my beer and check out this sh!t"!
If you want the latter, look elsewhere and start saving $!
On R10 vs R12, the Crutchfield comparison below only puts it as a difference between 29Hz (R12) and 31Hz (R10); however, it is a safe bet that there is also a significant difference in how loud they can play those frequencies which is not reflected in the charts. For a BR sized setup, I think the R10 would work well, for a larger room I'd look at the R12 (or two)!
https://www.crutchfield.com/S-sgnMP1tjBZ2/compare_108SUBR10_108SUBR12/Infinity-Reference-SUB-R10-vs-Infinity-Reference-SUB-R12.html
In case you are not aware, the R12 is currently available at $200 for refurbished units:
https://www.harmanaudio.com/infinity/SUBR12BK-Z.html?mrkgcl=989&mrkgadid=3308392364&utm_campaign=Con|GSC|Brand+(No+Product)&utm_source=Google&utm_medium=paid-search&utm_term=520457207964_channel_online_brand_infinity_product_type_components&product_id=SUBR12BK-Z&utm_content=Infinity&adpos=1o1&creative=289426932644&device=c&matchtype=&network=g&gclid=Cj0KCQjwl6LoBRDqARIsABllMSbZptSbXnGSmjyVeCy-f6OJwpY7rJI971mQGgkUuPcQGYdgcGX9--oaAuaoEALw_wcB
It does come with the standard (for new Infinity subs) 5 year speakers/2 year electronics warranty!