I have to say I agree with sunshine and know the first two houses she has linked in Earlsfield - Swaby Road and Leckford Road - as I used to live in a similar around the corner.
For the same price either of those two houses are a much, much better investment. Good solid 3 bedroom houses that have been extended with excellent downstairs space, gardens and both have off road parking.
They are super popular, close to the mainline station and Garratt Lane for shopping and going out. Many also then go up into the loft to make 4 bedrooms so offer potential to extend. They are close to popular schools so families also want them prior to moving out to places like Guildford etc.
But it's a young and vibrant area so not all family orientated at all.
In all honesty if I had to pick the maisonette near Clapham Junction versus one of those houses in Earlsfield I would hands down pick a house option in Earlsfield.
In fact that's what I did when I moved from Clapham South to Earlsfield many years ago.
However, lovely that maisonette is you will always get noise from upstairs and it will have a lesser appeal when selling in the future. I also do think it's a bit overpriced as well. It's already at the top of its game but the houses will always go up more in value.