I never use full Eco mode and by that I mean, using the toggle to switch from normal to Eco, I do however have Eco icon that pops up when driving a certain way in Normal mode.
The Full Eco mode did my head in, naff throttle response and lack of willingness to kick down got on my nerves. Even on long cruises I just keep it in normal and stick cruise control on. My day to day driving I get about 24mpg. Had 36 mpg after being stuck in a 50 zone for what seemed like forever. Generally get about 33-34 at national speed limit.
I drive in Normal Auto and Sport S in manual, prefer the gearbox and steering behaviour. Sport S+ is good when you know the road is gonna be empty. Few early morning blasts down to Goodwood have been epic, TVD can be awoken!
You could be cheeky and remove the vacuum line to the OEM airbox and it'll keep the flap open permanently so you get more noise from the get go. With aftermarket exhaust on, I have the ASC off all the time (although I think it's only actually active in the two Sport modes).