I live in a ground floor Warner on Perth Rd E10.
They've got good and bad points. Well laid out, easy enough to make alterations to, nice sense of community.
If you're a light sleeper then perhaps not a good idea, especially downstairs. I've done extensive and expensive soundproofing work on my ceilings and it's all largely pointless if they have hard floors upstairs. If you can deal with the fact that you will hear considerable noise (the loudness of which depends on how dickish they are, most residents hopefully realise that sound travels between the flats very easily), then you'll be alright! The noise comes from five neighbours too: upstairs/downstairs, both sides, and both diagonal sides.
Prone to dampness if they haven't been kept breathable over the years.