Danny - I have a Carrera Subway, the disc brake one. Prior to that I had the old Carrera Subway 1. The Subway 1 is essentially the new Carrera Limited Edition.
When I was looking to purchase I asked here whether I should go for the Subway Limited Edition or the Subway. The £60 difference at the time seemed to be for the disc brakes.
I am very glad I purchased the Subway rather than the Limited Edition. I have not had a bike with disc brakes before and I have to say I am a convert. They appear to require very little adjustment, stop much better than the V-brakes (the Subway v-brakes aren't great in the wet) and most notably the bike stays reasonably clean and is easier to clean.
At the time I looked at similar bikes in that price bracket. The Subway was the better specced bike.