A guy I met riding bought one less than a year ago as his first bike and he's already looking to sell it. He finds it lacks power on the highway so you might want to take that into consideration. Not saying that you should be buying a more powerful bike but you might want to buy one that's easier to flip if you need to in a couple of months.
Buying, registering, insuring, selling, buying another moto and all that over again is a pain in the ass.
If your friend had bought a 250 ninja or honda, sounds like he would have wanted to sell immediately then, considering a r60/5 has a higher top speed and hp. It also has more torque and a more usable, linear powerband, for new rider friendliness. Just another reason I think a 250 is a waste of time to purchase and inevitably resell when a 500/600/750 twin would hold you over longer before feeling the need to upgrade, and poses almost no higher risk.
Recommending a 250 is like recommending every 16 year old drive a 3 cylinder Geo Metro as a first car. Sure, it is the least risky option to recommend, but I think it's silly to ignore there are viable alternatives that come with marginally more risk.
If a r60/5 is too low on power, then I'd recommend an r75/6. They're usually $3k-4k on cl and ebay, all day long, for nice examples. My Dad bought his new in '75 and rebuilt the carbs once a few years ago. The thing fires right up after sitting for years at a time. They are extremely easy to learn and ride, and I still refuse to accept that they are anymore dangerous than a Kawasaki 300, especially given that it has nearly identical acceleration and power:weight figures. It's borderline moronic to make that claim.
Early /5s were short frames. And it wasn't an issue of being nimble...it was instability under very specific loads and maneuvering situations. BMW (then Butler and Smith) actually offered modified swingarms and subframes to correct this on the early bikes. You can easily identify a short frame from a long frame by looking at the swingarm welds.
^This. The short wheel base was unstable at speed.