I'm the third owner having bought the car in Sept 02 with 33k on it. In 7 years and 30k miles all it's required has been regular maintenance and a set of tires. Have had an MG, Austin Healey, Alfa Spider and a Sunbeam Tiger and several Mustangs a Firebird and some BMWs. The Miata isn't the most practical but it's the most fun for the least money and the greatest reliability. I'm 6'2, 185 and 60 years old. I fit it in it fine and don't need a break until we've gone for a couple hours. Buy one if you can find one with decent miles in good shape.
Handling, transmission, reliability and the option to go topless when you want to. Starts in the cold, which the Alfa wouldn't; doesn't leak, which all of the old ones did.
They've done what was needed with subsequent models. Plastic rear window isn't great, interior a little on the plain side.