I have 3 of them, All on Red, lucky 7, and Croupier. They have a very good motor in them and the Dial is awesome. The vibration is more rumbly then buzzy. on scale 1-10 (1 being buzzy 10 being rumbly) it is about a 6 and a half to 7. The All on Red is strongest (I've heard the black is as well). The others are just as strong but the Vibes arnt felt as well through the silicone as the Red version. it's really not that big of a difference only half a point on my scale.
I have two, the High Roller and Straight Up (sold). They are decent vibes for the price. I'd say about 4 vrooms, maybe 3.5 to be more exact but EF doesn't have that option on reviews. They are deeper vibrations.