I assume you are talking about the FD.
Get one with a fresh rebuild and there is no reason for them to be unreliable if looked after properly. They need a rebuild at around 60k normally, but some can go longer, some can go sooner. That's why it's best to get one on a fresh rebuild.
Also, you have to remember the rotary likes to consume oil by design, so keep on top of it.
Servicing is very reasonable, remember there is no cambelt to worry about.
Insurance is pretty reasonable, I'm paying 625 full comp, all mods declared (I'm 30 with 7-years NCD in a fairly good insurance area).
Be prepared for the fuel consumption though, they drink like there is a hole in the fuel tank. You'll get around 15 mpg out of a standard one. I get about 9 mpg out of mine when I'm going for it.......
All in all though they are just awesome cars. The handling is sublime, many describe the handing as 'like an overweight Caterham'. the power delievery is very addictive, the rotary loves to rev and you hit the rev buzzer before you know it. The brakes are incredible too.
All in all worth every penny it costs to run.
EDIT: The interior is very, 'enclosing', it literally wraps around you. It can feel clostrophobic at first, and if you are very tall forget it. I'm 6ft exactly and I
just fit with the seat all the way back. You can mod the seat rails for more movement fairly easily though.
EDIT 2: Go here:
www.mazdarotaryclub.com, the forums are a great place to learn about these cars.