I went through a similar evolution, owning first, a '66 MGB, then stepping up to the MX-5.
It was nice to have a roof that didn't leak, enough BTUs so you didn't have to decide between defrosting the windshield or heating the interior, and no oil stains in the driveway :-)
I put a set of really soft, gummy Pirellis on that car, loved taking it to some twisty backroads in the hills of Pennsylvania...
The myths about MGB unreliability are just that: myths! I have owned several MGBs that went literally hundreds of carefree miles between total overhauls. Miata? That's jap-lingo for "Pansy."