Having recently had my bike stolen and purchased a replacement a good lock was high on my agenda to secure my new purchase.
I heard many good things about the Kryptonite Mini 7 lock so purchase one of them but while it is a good, strong lock. I found it a bit of a pain to carry as it was too big to mount on my frame.
I doscovered the bordo line of Abus locks and they sounded like just the ticket. As flexible (ish) as chain locks but as tough as D Locks.
The lock is a good size, easy enough to get it round the frame, rear wheel and a fixed mount. Folds up in to a nice compact size which you can mount on the frame in its rubber holder.
The bars are covered in hard rubber to protect your frame as well.
When reading up on this lock I discovered that ABUS had released a sold secure silver rated version of the lock which I thought this one was. Sadly this lock is rated at bronze, as confirmed by the packaging.
Overall, really like the lock but ended up swapping it for the silver rated lock from my local store which was at the same price.