I went from MK5 GTi to Mk7 GTi last year, loved my Mk5 for 6 years or so, and a nice one will still turn my head - that said I knew I'd made a good choice on the drive home in the MK7
I've got leather but didn't going looking for it, but the rest of the car was the spec I wanted so I had to get it. I could live with out it but then it is nice to look at and gives a premium feel or thats what people tell me.
I never considered a Mk6, didn't seem much of an upgrade on the Mk5 and appear rather dated now, neither one thing or the other
- I'd say push yourself for a Mk7 if you can, don't think you'll regret it.