One of my issues is with the Japanese 'Harley copies" The TU250 is a nice enough little bike, but it is too small to really be freeway capable, even though it is freeway legal. But by far it's biggest fault is it almost total lack of character. It may as well have an electric motor. It has no "mechanical" feel or sounds to it at all. Far to refined for my taste. I have owned a ton of Japanese motorcycles,, and never loved any of them. They all seem "fake" somehow. And they are all way too refined, even the Harley copies,, which the V-Star 250 certainly is. I like my Ninja 500 not because it has character, because it doesn't, but because of the way it handles curvy roads. Still, an exotic, like an Aprilia or Ducati would be much better, and being European, I consider them the real thing. Ducatis have character, but they are not for someone who does not want a hardcore sportbike. Older BMW twins had character, but not the new ones. It has all been refined out. The Sportster 883 is NOT a large motorcycle, it is barely bigger than the V-Star 250. It is tiny compared to the huge Japanese Harley copy v-twins like the Kawasaki Vulcan 900, V-Star 900, Suzuki C50, and Honda Shadow Aero 750. Again the displacement might be close, but the physical size of the bike makes it look very small when parked next to one of those behemouths. It is also way smaller than the Bonnie, which is much larger than the '60s Bonneville, not only in displacement, but in physical size.
The only way to tell if you fit on a bike for sure is to go to a dealer and sit on it. And unlike the Japanese dealers, Harley dealers usually allow test rides.
One thing I can tell you, is that I own a Genuine Stella, and a Yamaha Vino 125. They both have about the same performance, other than the Stella can take off faster, and climb hills better due to it's manual gearbox. But when it comes to outright fun, the Stella is easily 10 times more fun. The Vino, while it will get you where you are going and back, is like riding a piece of Tupperware with wheels. It does have a motor, but you get no sensation of that while riding it. The Stella IS a vintage Vespa PX150E, made by LML in India, who once made Vespa branded scooters for Piaggio. There is nothing "fake" about it. The Royal Enfield was, up until a few years ago, still an exact copy of a 1950s Royal Enfield, made by a company that, again, made real Royal Enfield bikes for the Royal Enfield company until they went out of business, then the Indian company went right on making Royal Enfields, using original Royal Enfield tooling. Then the EPA and DOT got in the way, and the machines were completely redesigned to meet modern standards for safety and emissions. The same reason new Stellas wound up with a 4 stroke engine which robbed them of most of their character. Todays Royal Enfields use unit construction engines, and of all things, fuel injection
, which means a computer. They do still have style and character, and they are NOT Asian, which is good, but they are still too cheaply built for me. I love ancient design and character, but I still want some degree of reliability. My '66 Triumph had a lot more reliability than a Royal Enfield, once you got things right. By the time I owned it (mid '80s) there were a lot of aftermarket parts available to improve it. There were better carbs, better electrical parts, cables that didn't break, etc.
I would go to a Harley dealer, and try the Sportster. Then you will likely know if it is the bike for you. I have little doubt that handle it. If it does turn out to be not your thing, then you will know, and can move on to something else. Tou didn't say whether you wanted to do a lot of freeway riding or not. A Royal Enfield can handle some, though at slow speeds. It has about the same power as a TU250 or V-Star 250, or even a Rebel 250. But those bikes can be ridden flat out at '80 mph all day every day, while an Enfield can't. A Sportster can take you anywhere in the country, at freeway speeds, while feeling and sounding right, and without over exerting itself.
If you are wondering why I am posting so much about this, it seems as though you like the same type of bikes I do, and that is not common. Most people want refined, refined, and more refined. I want exactly the opposite. Go to stellaspeed.com, and you will find the same attitude. Most of those people wouldn't be caught dead on a plastic Asian scooter. They don't even like modern Vespas, because, you guessed it. They are too refined and souless. They do like Vespas, just not new ones. They like 2 strokes with manual shifting. Modern Vespas don't even have kickstarters, which is usually how I start my Stella.