The French robot forum kelrobot.fr, running on the same software as this site, has a forum designated "which robot to choose" involving varied opinions expressed. The questions are not simply who is best, but about suitability for particular aims. For example, what if you have two cats, or a big place or small place, or a particular budget, a location and particular model availability, or particular feature interest. Does one size fit all? The focus is thus a little different than simply reviews covering a particular brand in all its respects. The choice forum is an adjunct to the review section which serves as a database for the information interpreted in the choice forum. Information can be drawn from many reviewing sources both on the site and off. It is also a place where fans of various brands can express their opinions without being tied to discussion of a particular brand, and can make comparisons not relevant in a specific brand forum.
I do not know enough to recommend adding such a forum to this site and just bring the possibility to the operator's attention. I don't know, there might be an issue of whether such discussions can be misleading in their limitations.
The market has expanded with more robot suppliers over the years perhaps making such discussion more lively now, with more things to address.