I ran mine as a daily for 4 years with no issues. Fuel wise and everyone is going to say it to you, but if it's a major concern don't buy a Supra. If you're just looking for info, it will average between 22-25, if you're on the motorway the majority of the time, I'd imagine you'd see 27mpg. Servicing is no worse than any other car, but tyres etc can be expensive depending on what wheels you're running.
The biggest problem will be your hatred of putting boring miles on it. They're a fantastic car to drive and no matter what you come from you'll find them exciting. It takes a lot to get the best from a supra and that's a big portion of their appeal to me. Seeing the miles tick up as you do boring a to b stuff will 100% get on your nerves. They were built as a fast GT car, which is exactly what they are, fast, comfortable and a great all rounder, so in essence a fantastic daily.
best of luck with the search if you do decide to go ahead and get one!