I was actually sent a case of the 3M Select 31131 from 3M to demo for them. I used the whole case of Select 31131 and afterwards when contacted on what I thought about it, I told them I still preferred the Platinum Plus 01131 to it. Here is what I found to be the main differences.
The Select does spread a bit nicer, but outside the window, like overnight I found it to sand harder than the Platinum Plus filler. Also, I found as well as several shops in my area that the Select filler does have micro pinholes, and I don't get those in the Platinum Plus filler. I simply prefer the Platinum Plus. I also demo'ed the Rage Ultra, and found it to be almost like the Platinum plus, but it also sands harder next day or once outside the window plus it costs a bit more. My two favorite fillers are the Platinum Plus and the Rage Ultra. This was after demoing 16 different fillers over a 2 year time period. I usually don't select higher priced products, in many cases, but I did land back on the Platinum Plus 01131. Now with that said so you don't get confused 3M also makes a Platinum filler 01171, and I have not used that one. OFC, that came out before the Platinum Plus did. My understanding was Platinum Plus 01131 is a better version of the standard Platinum filler 01171.