WOW.. dont listen to this guy..
RWD is not worse than FWD, actually, since weight shifts to the rear of the car under acceleration, RWD cars have a small traction advantage over FWD, FWD cars have an advantage when it comes to stability, since the front is pulling the rear it helps keep the car straight. but your also asking the front tires to do two things at once when your turning.. turn and accelerate, which is why FWD is so prone to understeer, especially in snow, and understeer is much worse than oversteer in snow, with oversteer you at least have some element of contol over where the car is going.
if you have any driving skill you will be able to drive a RWD car in snow, just get GOOD snow tires (A MUST FOR ANY CAR YOU WILL TAKE SKIING!!) and if you cant handle a 2000lb 100hp car or at least not learn very quickly, you shouldnt be driving anyways.
as for reliability and parts, miatas have some of the best support for both OEM and aftermarket parts, you will have absolutely no problem at all locating anything you need, and for a good price. reliability wise, from my experience, they are just as reliable as any honda, toyota, etc.. they are very robust, well built cars.
my friend has a miata track car thats very low, has very stiff suspension, and he drives it everywhere in the snow, skiing, back roads to go camping, state park "offroad" trails in a foot of snow etc.. and its not a problem. with good snow tires its more capable than an awd car on all seasons.
go with a miata, its a perfect first car, well balanced, not very fast, reliable as hell, cheap to fix, its a manual, its perfect for learning how to drive and control a car. people that buy a brand new subaru lame mobile with traction control and an auto for a first car suck. basically ensures that you will always blow at driving..