The newer V-Max is speedier out of the box than the R3 Roadster, as well as lighter; I think it clocks in at 170 hp or some such. However, there's really no feeling out there like 204 nm of torque kicking you in the butt, and you can relatively easily raise the power numbers of the Rockets without any exotic addons like blowers or turbos, just naturally aspirated you can get to 240 hp or some such.
The Rocket isn't made out of lead, though.
The Roadster is admittedly in the 800 lb range but that's not far from your average cruiser. A Harley Road King clocks in at 800+, a Kawasaki Nomad in the tourer livery is 900+, there are tons of bikes that go high 700, low 800. And unlike those, the Rocket has the power and torque to handle the weight.
Handling on these is great. They're well balanced and the weight disappears once you get it to walking speed basically. U-turns are easy (turning radius isn't small, though) as is low speed maneuvering. On flat ground, you can easily peddle backwards and walk the bike back and forth, but if you park nose down and need to reverse out, you're not going to be quite as happy.
They handle twisties just fine also. Stock shocks are just passable, so for optimal ride people often spend $5-600 on shocks, but that's true of many bikes.
So my opinion, without having tested a recent V-max personally, would be that the Rocket is the nicer ride and having tons of torque at all revs is more useful than having 165 horses on the top end and a high-revving engine. You can use the torque all the time without having to rev the engine like a loon, and I suspect the accommodations in the rider's office are also more plush and comfy on the Rocket.
Might be relevant: