We get the odd ex-commission house here - 2 or 3 streets of the town are just these houses, all the same. They take an abnormally long time to sell and when they do they sell for a lot less than the old worker's cottages (which are comparable size). Unsurprisingly though they rent for the same so the yield on them is miles ahead.
So if you're looking to buy in an area where these houses are in an extreme minority among otherwise more 'desirable' houses, watch out. The 60s houses are extremely solidly built though, they just don't look so good.