First impressions after 1/2 hour or so...
I couldn't try a story level as the game froze when trying to load it - I'll have to try again later. So I went into a community level. Load times are somewhere between LBP2 and MNR
After waiting for the previous race to finish (you can watch) we loaded up and were off. You get a bit of free race time on the track before the actual race starts too.
Overall it feels more MNR than LBP, but probably because it was only race track type levels (crafty though) that I played. The speed seems very slow. Instead of boost pads you run over the LBP jetpack and get a boost, but without that the default speed is very slow. You can drift just like MNR with wheels catching fire and all, but I didn't see a boost meter filling. The buttons were messed up by default and maybe I was missing pushing the right "boost" button, but it really didn't seem there. Weapons were similar to MNR but just look different.
Having the grapple to cross gaps was kind of cool, but not much better than just doing tricks. LBP bounce pads worked just like launch ramps in MNR. Steering is very loose like MNR.
So I think with the LBP creation tools, and ability to make different types of levels other than pure racing, there is alot of potential there, but it definitely felt like MNR skinned in LBP. I really want to try some story levels to see what else might be in store assuming the really creative user levels aren't out there yet.