Never tried the new Road 5s. I don't like spending $240 on a rear, though.
I am a fan of the T31. I had both the T31gt and the T31. I prefer the softer carcass of the T31. I would buy again. Unfortunately, the $60/set Bridgestone rebate just ended Apr 30 (unless it was extended; I haven't checked).
I also recently replaced the Pirelli Super Corsas on my Tuono 1100 RF with the Bridgestone S22.
Before trying the Bridgestone T31s on the FJR, I went through several sets of Dunlop Roadsmart II before they changed they apparently changed the formula and made it more of a budget tire. I liked the original Dunlops.
I previously ran a set of Pilot Road 4 GT I bought in Grand Junction Colorado when I burned up a rear on a trip. It was smooth, but, again, I didn't like the stiffness of the GT. Also, the rear disappointed me in terms of life expectancy; did poorer than either the T31 or RS2. I wanted to like it, but I hypothesized more flex on the sidewall might have spared the tread a while longer.
I now now another brand new PR4GT on a new-to-me bike I just acquired. I'm enjoying the stiffness more than I did previously, but I'm still not sure I love the tire. It does feel "solid."
But, anyway, I wouldn't hesitate to recommend the T31 or the T31 GT. I'd probably get the T31. With the rebate they were like $240 a set from RMATV. To me that's a no-brainer over the Road 5s or the PR4. Even if they are "slightly" poorer, they definitely aren't $160 poorer.