OK, I've owned them both, many of both in fact, so I have a few comments. 1st, no way no how is the Triumph anywhere near the Fiat in terms of engineering. The Fiat is vastly superior everywhere, That's not to say the Triumph isn't fun, I loved them both, but they simply do not compare in terms of engineering, fit, finish, etc.
My first 7 was an '80 anniversary edition convertible bought when it was 2 years old. It was a great tourer, but not an out and out sports car like the X1/9. I called it a 7/10ths car. Beyond that and it was not in it's element. It also rarely went more than a few months between things like head gaskets, relays, oil leaks, top leaks, etc, etc, etc. But it was fun and I was sad to see it go.
On the other hand, I drove an X everyday for 7 years and was never once stranded. It did require maintenance, but if you did it, it was pretty good. Their biggest problem was getting someone to understand it when they worked on it. For instance, it is easy to do a coolant flush and not bleed the system, resulting in a blown head gasket. Keep in mind it was designed by the same guys that brought your Ferrari's. The engine is simply a jewel.
They also thrive on being driven very hard. Where the 7 is falling apart, the X is starting to shine. It's why they cleaned up against the TR7 in autocrossing back in the day.
Hoelscher's X1/9 was simply amazing. I was lucky enough to drive it numerous times, and his comparison between the X and MR2 is pretty accurate. The X1/9 is like a scalpel, the MR2 a sledgehammer. You can place the X wherever you wanted, while the MR2 bullies it's way through. Although similar on paper, the X is the true thoroughbred between the two.
Oh, and I love the MR2 too. My vote is buy the one you like the best, they're all great cars!
