Most critical in evaluating a car like the MX-5 are your priorities. If all you want to know is whether the new car is faster than the old car then the answer is yes. It's faster. Everywhere. However, if your goal with a new roadster is slightly less tangible, then pay attention because this next bit is critical. This is a very different car than the last Miata. Sure, it's faster. It certainly goes, turns and probably stops better than the second-generation Miata. However, in Mazda's hard focus to evolve the car to beyond-modern standards by keeping rigidity up and weight down, some element of the Miata we know and love is missing.
If the old Miata was a toy, the new MX-5 is a tool. Driving last year's car was like playing hooky from being a focused performance enthusiast--jump in, wail on the steering wheel and throttle and you'd be controllably sideways at every turn. The new car is fast enough and has enough grip that it's just not the same.
And this is the hard part to quantify. It's not that there's anything wrong with the new MX-5, not at all in fact--it's a worthy replacement to an aging hero. It's just that so much is different that it's hard to recognize. We're used to Miatas shaking. We're used to Miatas being underpowered and still fun. And we're used to sitting on them rather than in them. All that is gone.
The hard-core enthusiast in us wants to say good riddance, never needed all that crap slowing us down anyway. But the nostalgic sports car guy has a harder time letting go of the only brilliantly underpowered sports car we ever loved.
So, sure, if you want to go quicker this is the MX-5 for you. If you want to be nostalgic about all the compromises that made the old car a Miata, go buy a used first-gen. car for one-fourth of the price. Either way, you'll have a Miata. And either way, you'll have fun.