You CAN keep it. Although they do require a little more attention to details on a regular basis - it's just that - attention to the details to keep it running trouble free.
The 2 valve engines are fairly easy to work on. You don't have to be a mechanical susperstar. Valve checks and adjustments are not hard to learn. I check every 3K and expect to adjust some of them maybe every 6K miles. Changing belts every 12K miles is easy and not too costly for the DIYer.
Even though I'm a tool fanatic, I haven't had to get a lot of specialty tools.(I have bought a lot special tools, but didn't HAVE to) First off, get a Haynes Manual. Chris at ca-cycleworks should have it in hardcover (more durable). In addition to lots of good info on the bikes systems, it has invaluable tips and tricks for making some of the special tools you'll want or need. This board and several personal web pages with maintenance info are a fantastic help for those of us who do it ourselves.
The basic tools you'll need to perform routine maintenance will be a set of metric wrenches, metric allen wrenches, metric allen type sockets in 6mm, 8mm, 10mm (and 14mm if you have the earlier solid type front axle), spark plug socket, torque wrench for starters. About the only metric socket I use regularly is the 22mm (I think) for the rear axle nuts. A decent vernier caliper, micrometer, and feeler guages round out the necessary measuring tools. Nice to have items include a compression tester and a multimeter for the occasional electric gremlin. I've added other stuff, and splurged on a set of T-handle allen wrenches because so much stuff on the bike uses them, but the basic list will get most stuff done
I made a cam belt tensioning tool as per Haynes from a spring scale with a custom bent hook on one end to hold on to the roller bearing while setting the tension. I made a little hook for pulling the spring clips off the rocker shafts more easily from an old ice pick with the end bent 90 degrees. (You find yourself taking these clips off and on several times while checking/adjusting the valves).
Not all valves need adjusting every time. As your bike gets past the 12-15K mile mark they should require fewer adjustments. At 12K when I got my bike I had to adjust all 4 openers and one closer. I checked them again at 15K and had to adjust one opener. Sometimes if more than one valve needs adjusting you get lucky and find that the shim coming off one valve may be the thickness you need to correct one of the other valves. Some dealers will give you a few dollars "trade in" on old shims. I just keep the few I have left over after buying the necessary ones in case they will be right for a future adjustment.
Hopefully this reply will calm some of the new-owner concerns. Yes,things can get expensive - but barring catastrophic failures, the basic stuff isn't that bad if you are mechanically inclined enough to do a lot of the work yourself. More than maintenance costs, you'll probably have to learn to control the impulse to spend $$ on more mods for the bike.