This is really not much of a rumor when it comes down to what was said, but it is talking about the new Primaris Bikes and it can be assumed that the new models will not suck, but instead be rather powerful. So here is what was said.
via Gederas- on Bolter and Chainsword
Alright lads, back home from work now, so I return bearing more rumours from the pocket playtester:
this was in response to someone saying he wants to offload the bikes:
"Yeah I would hold on to those bikers, they are crazy good."
this was me inquiring to what he said above:
"crazy good how? Because unless they have any some kind of funky rules all I see are just chainswords and twin both rifles Unless you're referring to the fact that they'll be zipping around with three wounds a 14-inch movement and toughness 5?"
Which leads into this, which is the most important bit imo:
"Yeah they have some other stuff and the profile is better
They be legit tasty for all marine factions especially for ones with bonuses to combat
I think WS, BT, BA, DA, and SW will all do well with a load of these.
I think they may be the most “competitive” choice from the models previewed thus far"