I upvoted because you mention this. startups are founded because not the tech but the team behind them that will follow through it.
The team have built 2 blockchains so far, Bitshares and Steem. This is their 3rd. So you're investing in a team that has successfully built and run 2 blockchains.
But the tech they help build also helps build up this ecosystem ;}
For me the best opportunity that runs on graphene is Peerplays. They will owe their thanks to this tech.