Yes, the 760 beats the 270 in performance.
Does it justify $90? Well, assuming the MSI 270 performs relatively similar to the Asus 270
, the difference is 20FPS, give or take.
20 FPS can actually make or break the playability of certain games. So yes, I believe it's worth your money.
Though, depending on availability you might be able to purchase a cheap 7970 for around the same price as a 760 but with much better performance.