i guess the RB3011 should do this trick just fine.
i was running a RB2011 500/500 with 2/3 vlans, caps ,multiple vpns and +- 8 users.
without setup of igmp, i dont see a problem here.

i had this sort of issue too, with a CRS328-24P-4S+ arm, routeros

IGMP snooping on the bridge, no performance,
IGMP snooping off, works, but you see all trafic go to all ports.
IGMP snooping on, and enable Vlan filtering on the bridge. - works!