Welcome to NSR-WORLD.
They're all pretty good, and the later the model the more easy it will be for you, but also the more expensive.
Best "bang for buck" is an MC21SE. Most expensive for many reasons will be any MC28.
If you go for an MC18, get a Mk2 (R5K, or R6K-SP if you can find one). MC18 Mk1's (R2J or R4J-SP) engine parts are becoming more difficult to source, so I wouldn't recommend one to a first-timer.
Just about everything is available used from Yahoo! Auctions in Japan, and we have a Supporting Vendor in the Members Area who can help you purchase any of it.
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Andy.
NSR-WORLD.COM
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