The ring land failure on a friends car may be down to low oil levels, rather than hard driving.
As Jay has said pretty much said everything, I will just say that I love my hb after owning a classic 95 WRX for 11 years moving upto the the 08 was a revelation a much more refind drive.
The ride isn't harsh at all on normal roads, I regualy take speed bumps with out coming to a stop. it doesn't sound any where near as harsh as the Civic. Again like Jay I am looking to get some springs and firm the ride up a bit. Maybe some urathane bushes aswell.
As for the ring land failure, as long as the car has got a full serivce history and you get it checked out by Jolly Green Monster or Andy you should have no issues, if you keep the engine standard or don't go for Stupid power.
My impression is It was mainly modded cars running 400+ bhp that suffered it.
The only complaints about the car I have are:
The stupid Central Locking.
The cargo cover creaks and groans. I had to use some foam to stop it making noise.
The ugly huge Forrester wing mirrors.
Not that much really, they are great cars and can easily return upto 22mpg urban if you drive like a granny. I average 18-19mpg urban, driving like normal with a few spirited squirts every now and then.
When you go for a test drive make sure you try the car in S# theres a little dial by the hand brake turn that to S# and hold on tight. if that doesnt put a grin on your face then i don't know what will.