I've considered it, but I've never actually done it. From what I've heard, the time you spend organising all the catalogues at home means that it's not really worth it. If it was just newspapers I might be more interested, because I do enjoy a walk through the suburbs.
I do it now, only because I don't have a proper job and it keeps me occupied and brings in a bit of extra money.
But my agency does different suburban areas each week so I get a change of scenery, I see plants/trees in all seasons and have built up my fitness so I can now do 2-3 hours of walking a day.
My sister did it for a week. It was absolutely ridiculous. The money is not worth the amount of work that is required. We quickly realised that she wasn't going to meet the deadline she was given. Guess who had to help.
No I haven't but I know people who do deliver to mailboxes. It's hard work and thankless really because the money is dreadful (but that depends on how much you need that extra money). I have great respect for the people that are willing to get out and do the hard slog.