Oooh - we have one! Best thing we ever bought for our garden, which is pretty big (.98 acre but lots of trees too). We are not natural gardeners (what WERE we thinking - I don't know) but all we have to do is whizz round (in less than an hour, including all the tricky bits) and the garden looks fab! (if you ignore the weed choked flower borders)
We bought ours from a local dealer. Can't remember the exact price, but I do remember that the self powered push along big one we would have bought was £200 less, and we are most grateful five years later that we spent the extra. You can get reconditioned ones, as my BIL has done, and his is the same as ours. Ours is a lawnflight tractor mower, 32" width cut, various heights (and we keep the cut long, as the garden is so unlevel), and requires a service once a year to check oil, battery, general condition (But I think a decent petrol mower would require the same thing) and our local dealer comes, collects it, does the biz, and drops it back within a few days. It picks up the grass clippings, and you can buy all sorts of attachments for it (like scarifiers, trailers etc).
Worth pointing out that as most of these tractor mowers are for US audiences, and they cut their grass less short than we do, that it's worth checking that out if you want a really close cut.