There is a wide gap between new platforms and the best platforms.
Look at the communities of Dove, GenerationBenz, MetroTwin, AirFrance's BlueNity or SCJohnson's Right At Home all use relatively new, modern, platforms and they look great. Exactly how a modern website should look.
Except a community platform is different from a website. The purpose of a community platform is to facilitate interactions between members. A community platform puts function before form.
Compare the above examples with CareSpace, Teacher's Connect, The Student Room, MyGarden or (my favourite) Backyard Chickens. These platforms are ugly. No self-respecting organization would want communities which looked like this.
But this is exactly what they should want.
These platforms are incredibly successful. They have over 15m posts between them. They are proven to work. These are the platforms other organizations should be imitating. And the best news is, they're cheap.
When you're developing your community platform opt for something functional which is proven to work. Don't develop custom community platforms sites without a track-record of success.