To be perfectly honest, if I were you I'd be buying a Fiesta ST instead. Or wait for the new Ibiza Cupra (2017? 2018?).
I totally agree. I wouldn't buy any Ibiza to be honest, Cupra or not. It has felt tired for a long time now. Ibiza has always felt like an elderly polo, and the polo is dull in its freshest configuration. You'd have a lot more fun in the fiesta ST.
I bought my Leon because it didn't feel like a compromise. I saved money by going without the bits I couldn't care less about, like a VW badge or softer carpets, and in return got a decent spec car made with all the same parts as the latest Golf.
In the Ibiza you're getting a generation old Polo. It just never felt finished. It's the little things, like being able to see the exterior body panels from inside the car - look at the boot lid from the drivers seat for a perfect example. The Leon had to be good when it launched as SEAT needed the customers. The Ibiza meanwhile had to be cheap, and it shows. The fiesta ST has it trumped in every area.