Coming from a guy whos owned more than 13 rotary powered vehicles...
Pro's - Fun motors, extremely smooth running, good throttle response, easy to boost, super light, have a good top end powerband and are incredibly powerful for their size, reliable with proper care
They are not good for supercharging...very rarely do people supercharge them, but turbocharging yes, and they are very easy to work on
Con's - Really bad gas mileage. And depending on what year (1993-1995 RX7 for example) Expensive maintenance
The only reason people say they are unreliable is because the owners dont take care of them properly.. Ive had friends and had a N/A RX7 last to 350,000kms when i sold it. I sold one of my turbo FCs which i got stock, then fully modded (garrett turbo, microtech ECU etc.) and beat on every single day and sold it with 180,000kms still running fine, its all about how you take care of the motor and the tune
Heres a animated gif simply showing how it works
Edit : Ok just noticed the OP's post date..Why was a thread from 2009 bumped
lol