Jhere you might be better off asking the question on the MN Local Sutton site talk board?
FWIW DS goes to school in Sutton (although we are neighbouring borough residents). It seems a bit rough in parts and not nice to be walking about in the town centre after dark, but the same would go for most areas (certainly in London)? AND it is home to one of the largest council estates in Europe. If you get off in town near Matalan you get a view that's possibly distorted. DS always advises against getting off there - for a reason.
But frankly having been a London resident all my adult life (and having lived in Tottenham for a while), I would call Sutton 'tame' although there is an 'underbelly'. It really depends what you're used to. Personally, I felt more threatened living in a very pukka part of Wandsworth but that's because one is more likely to be targeted there for having money.
I think even the lower end of the town centre will change now that there's the massive Sainsbury's open and that part of town is rapidly undergoing regeneration. The 'top end' is too, so I'm sure Sutton will become increasingly desirable with the passage of time.
Cheam is lovely,and as someone commented up thread if you take a bus route from Sutton Station through to Epsom you will come across a huge spread of houses in the £750K+ bracket. And decent size family homes with gardens, not two ups/two downs that would cost the equivalent in other parts of SW London (Wimbledon included).
Always worth checking out how many of the people who are being critical of an area actually live/work/school there. Although I do know long term residents and former residents of the borough who do acknowledge that it seems to have got rougher in recent years. Not sure if the crime stats support that though - it could just be that the digital age has brought all 'crimes and misdemeanours' to our attention in a way we'd never previously have been aware of them?
Many of the local primary schools have excellent reputations too. But can't comment directly as our children didn't attend any of them. Certainly Sutton is consistently one of the highest achieving areas (top five) in terms of GCSE grades in the UK. And many families do flock to be in catchment area, not just for the grammar schools but the many sought after comprehensives too.
The only thing I would say is that there's been a bit of a recent dip in family activities venues, particularly in Sutton itself, with the loss of the theatre, bowling alley/laser tag and now even Little Lambs Softplay (which I think has moved to Banstead). But possibly only a temporary blip, and with Merton, Kingston, Croydon and Epsom easily accessible by car/public transport possibly not really a problem anyway?