REL T/9i compared to Strata iii

I currently have a REL Strata iii, using with Harbeth SHL 5+ 40th anniversary speakers in my 12x18 living room. I have a bedroom system using Harbeth P3esr 40th anniversary speakers with no subwoofer. I was thinknig of a REL T/5i or T/7i with the P3s. The thought then occurred to me to get a T/9i for my main system and move the Strata iii to use with the p3s.
Anyone have any experience comparing the T/9i with the Strata iii? I am not interested in suggestions of another brand of subwoofer. I like the REL set up. If the T/9i does not best the Strata iii I may leave the it in my main system and go with the T/5i or T7/i  in my bedroom system with the p3s.
I kept my stadium 3 over the S/3 I had for a year.  Different subs but hope that helps.

     Restricting your sub choices to a single brand or type makes no sense and just displays a willful ignorance that harms no one but yourself.