I'm a big fun of paint from the main manufacturers (eg. Bristol, Dulux, Taubmans, Berger, British Paints) in a premium quality range!
I do not believe that any particular paint brand stands up significantly in quality, even if they have a different pricing and amount of TV commercials :))). Paints of the same quality range are actually very-very similar. They all are consistent, with a good coverage and long term performance. They are widely available as many shops stock them.
I try to avoid “Designer”, “Boutique” and "Hand-Made" type of paints unless the client specifically requests them. I found these often require more coats, may differ from drum to drum in colour and texture. I've seen some paints changing colour or texture significantly in a short period of time. Also they usually are much more expensive.
But it is true that some designer brands have some unique finishes that can't be reproduced by any major paint manufacturer.