I'm a bit on the large side. I have sat on the V-Star 650, and have put some miles on a couple of Sportsters. I found the V-Star a much better fit. It felt bigger to me, the much wider gas tank may have had a lot to do with that. But the pegs/seat/bar layout seemed more spacious as well. The Sportsters had mid pegs. You can get forward pegs for them that would give me a lot more leg room, and you can get any kind of bars you want. So a Sportster could be modified to fit me ok. One big difference between the Sportster and the V-Star 650 is weight. I don't have the numbers, but the Sportster is one heavy bike for it's size. A lot of that weight is probably the engine, which is built like an anvil to handle all the shaking caused by the single crankpin long stroke small bore 45 degree engine. I doubt a Sportster 883 has any more power than a V-Star 650. They certainly feel like they do, but a lot of that is just noise and vibration.
The 900/950s are a nice size, and so are the 1100 and even 1300 v-twins, like the V-Stars and the VTX1300. Any 1300 will carry you and a passenger across the country with ease. Anything bigger is just an image thing as far as I am concerned. I had a 1500 for a while till it blew up, it was a lot slower than many much smaller bikes I've had. And it was heavy and handled like a dog. Would have made a good interstate touring bike though. My most powerful cruiser was probably my 1980 Yamaha XS1100 Special. It would EASILY leave ANY v-twin cruiser for dead.