Octobrush Stats:
http://vm.whatasha.me/splatoon/files/wep_values/RollerBrushNormal.txt
It's basically the Ink Brush with a lower Ink Speed and Mobility stat, but a higher Range stat in exchange. Its run speed is slower than the Ink Brush, but faster than the Carbon roller. It's ink trail is as you'd expect noticeably wider than the Ink Brush too sitting just short of the Carbon Roller's width. Its Splash range is greater than both the Ink Brush and Carbon Roller. Its splash damage is 37 per hit so it's a 3 hit splat unless the bad guy has the equivalent of at least two defense Up main abilities.
Overall I'd say as far as just the main weapon goes, this is likely to be a much better brush than its Ink brother. It makes up for what it lacks in both ink splash range/damage and ink trail size while still maintaining the overall high speed in both movement and swiping the brush category is known for. Its main set might not be for everyone, but its alternate set is the same as the Carbon Roller's main one (Burst Bombs and Inkzooka) which is arguably a much better fit as just like with aforementioned roller, it helps to cover for its range issue somewhat.
All that said, it's still a brush and as such will most likely never be able to hang with the big kid weapons in any sort of serious competitive environment. Still, it has the potential to be a lot of fun all the same. I'm definitely looking forward to it.