I think Mazda's reliabilty is close to Honda/Toyota, but still not quite on par. I don't forsee any major issues with the 3, but I would wait until next year to pick one up. Usually small problems are present in the first production year. The 6's had faulty foglight wiring.
The 7th generation Civics even had problems when they were released in 01. My brother's has little issues that were resolved for the 02+ models.
I need to make a trip to the dealerships to see the 3's when they come stateside