In fairness I've not lived in Balham but I would also big up Earlsfield. I live towards the Tooting end and I feel like I have the best of both worlds - the trainline and more grown up atmosphere of Earlsfield and the tube and more edgy vibe in Tooting Broadway (which is now seriously cool and has a fabulous selection of pubs, bars and restaurants). Toots also has useful shops like Boots. You can also walk to Wimbledon Park tube if you don't mind a bit of a stomp.
If ofsted reports are your thing we don't have any outstanding schools any more since BP was downgraded this year. Still both BP and Smallwood are good with outstanding features and people also speak highly of Earlsfield Primary.
I really like it here and as has already been said it feels a bit calmer than Balham.