I used a Coopers Real Ale tin in November to make a brew for xmas and over the summer. Didn't add anything to it at all but water. Wanted to see how it would turn out and figure out from there what I need to add to suit my tastes.
I consider the Iso hops in it very harsh. I've only ever used Black Rock malt in the past and treat my hops gently.
As far as the yeast is concerned, I am aware that it is a different strain from that in the bottled stuff but I think they have done a good job finding a match.
I wouldn't add any extra fermentables as I like light beer because I can drink more of it.
All in all though a pretty average beer. I'm only using the Coopers tins because they're cheap and I'm planning to do split batches to test flavour variations using different yeast, hops etc. Hopefully the tins will give me a uniform base for making accurate comparisons.