Hey there
I bought mine from MazdaManiac here on this forum. The local tuners either don't carry or don't know how to tune rotaries properly. I bought it from him for about 700 bucks .. but I think that the price went up lately. He personally tunes each map for your car (you have to do a series of data logging). Lately, his turn around for maps are super quick (2-3 days).
Check out his website
www.mazdamaniac.com ... he's associate with BHR (Black Halo Racing) who are also vendors on the forum.
As for the value ... I personally feel it's worth it because our cars have alot of potential both in power gain and fuel consumption. I personally found that the car is much more responsive AND better mileage (go figure!). Mind you I'm NA, guys on turbos and such find even more gains.