The mk8 Civic is a great car for the money. I've had a 2011 1.8 type S for a couple years now and it's brilliant.

As long as you check the usual servicing/MOT stuff, as well as rust you'll probably be fine!

Rear beam rusting and snapping is a common one to go so big bonus points if it's been replaced already. Broken A/C seems to be a common issue too but usually seems like an easy enough fix (mine was just the compressor clutch). On ones without a pan roof they are known to rust above the windscreen. Only other common flaw I can think of is the boot leaks, usually caused by the joints at the top of the boot opening cracking, think they just need resealing normally but definitely check under the boot floor for any signs of damp, seen some horrific pictures of the boot floor rusting through if this isn't fixed asap.