I still have a 1997 BMW F650ST. I think it rocks even though it will give you sore buns; but to match the Vs. 650, you would have to get 1) a Bombardier DS650 Web cam high lift/short duration cam (similar to Vs. 650 midrange cam), 2) buy a Husky TR 650 enhanced top end (BMW 650) racing bike, or 3) get a turbo which few have been done. You will spend up to $5K more for these options complete (although I'd like a Strada TR650 Husky cheap - in addition.)
But rather than do that, it is much cheaper to buy and maintain a Vs. 650.The performance and reliability would be hard to equal by any of the others for all round riding. A thump is nice, but add in the supermoto chassis too, and there are a few more thousand dollars to match (actually though, the Husky TR650 may come close but 1) it's a one-year wonder discontinued bike and 2) it's not Japanese.)
All motorcycles are fun to drive, but I don't know of any more fun than the Vs. 650 at most of the speeds we drive and most of the time. Racetracks are a different story maybe, but that is apples and oranges. Racing motorcycles is way beyond what I want to do, like the offroad image of the BMW 650's, but that is what sells high profit margin bikes that are rarely run for racing or offroad. Most of those owners get their (bike image) thrills 5% to 10% of the time (estimated), whereas I enjoy my sports-touring deluxe close to 100% of the time Safely! ymmv
And the BMW GS650's (efi) do not have any low middle range, like noted in the video above, but they get good gas mileage. BMW needs Aprilia or Husky to help them design their single cylinder engine bikes, imo.