It really isn't radically different to the Mk7. The most radical change is the dashboard and the buttonless dash. Other than that, many of the reasons i chose a Mk7 are still there in the Mk8. Most of the complaints on here about the Mk8 just seem superficial to me.
I've come to realise over the last few months that the dash isn't going to be as off putting as i'd first feared. Unless you're constantly fiddling with the heater controls and headlights while driving (and you shouldn't be) then it isn't a major issue. At least most of the functions you'll actually need are easier to see than they are in the Mk7, as they're located higher up the dash in the Mk8.
Losing the gas strut under the bonnet is a bit of a shame, but in the 2 and a half years I had my Octavia I didn't feel like not having one was a good enough reason to choose a different car.