I thought the same about them till I bought one for my wife when we got engaged years ago, I promptly wrecked it right after our wedding, literally 2 days after our honeymoon. That one was a total write off. Fast forward a few years, I got my hands on another one for a decent price. 1200$ Came with some mild mods, springs, shocks, rear sway bar, 15's with 205 series azenis on em, semi aggressive alignment. WOW what a difference, I seriously intended for this to be a replacement for my wives car that I wrecked. Nope, I have a hard time handing over the keys, I daily it, I had intended to track/autocross it occasionally but I'm afraid of the results if I do. I've since replaced the azenis with 225 toyo's and while the razor sharp turn in has faded, lateral grip is nuts, the seat is the limiting factor now, even with a foamectomy done, I can't corner anywhere near the limit on the street, even in the rain, I've tried to cross it up, it just jerks around a bit, and slows way down, it truly is an amazing car. (just to clarify that, I live in the middle of nowhere, my closest neighbor is literally almost a mile away via hard top, so I have plenty of empty street to play on, and the neighbors are used to my shenanigans)
I have the same gripes as everyone else, noisy on the highway, (no biggie just take the backroads more often, more relaxed drive anyway), AC is so so at best, can be an issue some days in the florida heat, soft top flat sucks at keeping out heat, and cold. yeah you get the gay, girls car comments but I just look at em and smile.
But the benefits far outweigh the drawbacks, I deliver pizza in mine at least once a week, have taken it on 1500 mile road trips, again, buzzy on the interstate, but the ability to squirt through traffic more than makes up for it. Cops tend to ignore them, as most of em have never driven one. Parts are relatively cheap, easy to work on, easy to modify, face it what ever you want to do has probably been done at least once before and documented on the web. Amazing handling, it's stupid really how capable this car is with the few mods that have been done.
You do have to wind it up a bit to really get it to move, but once you get used to driving it, everything else just seems tame. It really does talk to you. I find myself running around without the radio on quite a bit, just listening to the car.
Last thing and then I'll stop raving about a miata. I picked up a 95 Integra, last december, I've put less than 6000 miles on it since it's purchase(I avg 18-20k a year on my vehicles due to the distance to town, and work). I literally walk past it every day to get to the miata to go to work. In fact the teg is going up for sale in the next couple of weeks. I just don't drive it enough to justify keeping it. Probably going to snag another miata for my wife. 
Ask Tom or anyone else who has seen me autocross. Pretty much crossed up every turn.
