I'm personally tremendously excited about FundersClub. It seems like they have the right mix of a hands-on, closed system (for fundraisers) and self-serve, open system (for accredited investors, more or less).
I am curious how much each startup has raised through the platform, though. They claim over $26m in total, split over (at least?) 8 companies: https://thefundersclub.com/site/pastinvestments/