Maybe not the typical Lexus competitor but then again the RC-F isn't your typical Lexus.
On the surface the two do share a remarkable similarity, Naturally Aspirated 5.0L fire breathing V8's, coupe styling, 400+ hp and the dynamics to back it all up (we hope). A real detractor for the RC-F is the lack of a 6MT, I'm also not sure if the RC-F has a mechanical LSD I havent seen anything mentioned as of yet, but thats just me.
Some people claim that the RC-F will be technologically superior to the Mustang, but I'm just not seeing that. Ford put a ton of effort into thhe mustangs sophisticated driving modes and track suite apps that were developed in the last gen BOSS 302.
I think where the Mustang gets the real edge is in the engine department. The Coyota 5.0 is a proven monster with plenty of aftermarket support. In its current form the Coyote produces more power than the V8 in the IS-F. So for spec shoppers that could be the difference.
Of course I think it all comes down to intended use. As a daily driver the RC-F should prove to be a far more comfortable and refined package than the Mustang. As a weekend fun car, theres not much doing. But then what do you intend to DO with the car? For modders the Mustang is by far the better choice. More aftermarket support and way more upward potential in my opinion.
So the question becomes will you spend the extra $30K for the Lexus?