I've been playing it for 18 months now - absolutely love it. The benefits - exercise, great physically and mentally, as well as socially. Believe me you can get out of breath playing this sport (ok, I am not the fittest/unfittest). The best thing for me are the kickabouts - 20+ of us turn up and divide into four teams ensuring each has a keeper, defenders etc, and we play as many 10 minute games as we can in an hour. Great stuff. I also play in two teams (in different leagues) in Derbyshire - the standard is very good - played against some lads from Derby Community - when they actually signed up to play Derby County arranged for it to be done at Pride Park and arranged photographs etc. Also played against a team from Burton Albion who were pretty good - beat us 9-3 (matches are 40 minute games divided into 4 quarters) !
If you go on our local FA's page our google your local FA and "walking football" you should find a link to a kickabout near you. I thoroughly recommend it - I'm 51 and work part time so I can fit n a day time and one evening kickabout/match when the body permits.