While not ever having heard the Ren 80's I have listened to the 90's. Had 2.5, 4.5, RSIIb, RS1a, and a bunch others including the PSB Golds. It's more of a preference of the way you like to listen to music. I prefer the wider soundstage. I hate the in your face and small imaging sound. For the life of me I've yet to figure out why you place one chair in the middle of two speakers to listen to music. I like it all over. Even prefer 7.1 stereo when set up. But, I've usually had the advantage of being able to have the room for both listening and home theatre usage.
The 90's didn't sound bad at all in the spot. Even a bit off center they still held up. I just like the wider sound. The PSBs didn't last long as I was too used to the sound of the 2.5. I have hardly ever had any trouble positioning the 2.5s. Now that I am running the RS1a's it's almost back to MY version of music nirvana, with my version being compared to when I had the 4.5s.
It's awesome that you are exploring the nuances of speakers. It never should stop as I've made it a point to do just that and lately with the newer speakers. There's some glorious sound out there but for some reason I always come back to Infinity.