I have used Rosediy own brand paint.
I have used their own brand 'primer/undercoat' and i think their paint is a bit too thin. First time i painted my walls it looked so thin as each day went by, i could almost see the walls through the paint. Some people will tell you an undercoat is supposed to be thin and you need one coat, some will tell you the walls need two coats - the important thing is, you have to mention you are using a diy stores own brand and you think the paint is a bit thin.
I went back to the shop to tell them, they recommned a second coat. At £20 per 5 litre bucket its not worth it, i have now spent £40 on 2 layers of undercoat only.
Now think, if £20 per 5 litre bucket is half water, then what are you getting for £10 a bucket of 5 litre - maybe more than half a bucket is water.
I have given my walls 2 undercoats and it looks ok but in some places it looks a bit thin again, might need a 3rd coat but then i might just paint over only the bits that look thin. Luckily, this time i have a bit more paint left so maybe i wont have to fish out another 20 quid. I think it'll be ok if i just do a 2 coats of my final colour which i just bought from a paint shop in my local area.
This time i bought dulux which is 12.99 for a 6 litre bucket and the same paint at rosediy is £15.
A friend of mine recommended rose diy because they do cheap at £10 per bucket and he said "its just as good" as branded paint. What he didnt tell me is you only get what you pay for.
btw, its only white matt/emulsion whatever they're selling (i forgot) is £10. magnolia or eggshell (which is wipable) is £25 - £30 for 5 littres.
Basically, its not really a good deal specially if you can get the same wipable paint at 6 litres for 12.99
I heard if you cheap paint, someone had to do a 3 coat (but it wasnt from rose).
Do not go for DIY stores own brand as it is thinner and you might then need to put on a third coat. If you want a good finish go with 'dulux', whats a few extra quid. Don't scrimp it's not worth it. The price difference is essentially in water content. Expensive paint is thicker though it doesn't roll as far, you only need 2 coats to build up colour.