The difference between a Supra and a Corvette is that the Supra actually handles well.
It's not an FD RX7 in that way but it's overall a better car than the FT-86 can ever be in my opinion.
Are you sure the Supra costs that much to maintain ? General idea HERE I live is that it's quite cheap! I never heard of anyone breaking down really...
The 90s era JDM cars (300zx/R32s/Supra/RX7) were against real competitors like the 911/F355 etc.
The FR-S/BRZ will be competing to beat a Hyundai Genesis or struggle against the out of production RX8 which is more practical, less reliable, drinks more fuel and probably a tad better car in power/handling (there's still the Spirit version coming out tho but no performance upgrades if anyone is interested:P).
My opinion is if you're cross-shopping a Supra and a FR-S then the FR-S shouldn't be considered. I doubt there's a new car to compare with the Supra, the 3.0L TT is a dying breed at the moment... They are simply not in the same league...
An FR-S sounds great and I hope it does well, I will not be buying it though (at least not now, maybe in 5 years/if they come out with a 300hp version).
Also whoever says the Toyota FR-S will be an investment or holding value then you're mistaken, check out any Toyota MR2 SW20 and tell me how they're holding up against cars from the same age, they plummeted. Apart from the Supra, nothing else held its value... Food for thought !
I won't even go into Subaru cars, they depreciate like a block of concrete in a river...
(I know, I own one :P)
Take my facts with a grain of salt, I live in the EU and we get RHD cars
To sum up my advice:
If you definitely need to buy a new car for all means wait for FR-S and BRZ, see prices/compare options and so on and choose between the two.
The Hyundai as good as it is, it looks ugly for me and it's a Hyundai. I'd prefer some heritage from a sports car :P
If you can manage the fact of a used car, you can find a lot of cars equivalent or better for same/less/much less money. May need repairs and they'll have some years under their belt. Calculate the depreciation of a new FR-S over 60k miles/5 years or whatever versus the costs of repair on an older car...
It all depends on what you're able to live with and what you want.