I think the new design is a regression compared to the previous one ; I personally find it ugly, lacking personality and with a RIO branding mostly hidden.
The new feed concept is a real chore : I'm used to opening interesting threads in new tabs before starting to read, now I can't anymore ...
This is going against a big web design must-have basic quality : usability.
Furthermore, when you read a post from the feed you don't have access to the page link / permalink ; this is really another big mistake, that you rarely come across after more than 20 years of hyperlinks usage.

I just tried it on Opera; you display a message that :
"Your browser isn't supported. Due to this, the site may behave unexpectedly." lol, this is ridiculous ! RIO should be compatible with all modern browsers, and the funny thing is, that the only problem I observed when using Opera was your warning message itself which blocks the menu; remove it please.

This must be costing you money.

3 bugs I noticed :
- on FF (OK on Chrome) title div of thread accessed from the feed is positioned too low
- when reducing the width of the window, the content div gets greyed and unaccessible
- when reducing the width of the window, the hamburger menu isn't clickable (nor the expandable personal menu on the left)

Anyway, I couldn't care less, because RIO content always keeps improving :-)