This is a fairly drastic simplification. There are a bunch of different pieces of QUIC, (not least, sorry I'm not authoritative either) - SSL and "TCP" handsha

This is a fairly drastic simplification. There are a bunch of different pieces of QUIC, (not least, sorry I'm not authoritative either) - SSL and "TCP" handshake are collapsed into a single transaction - That transaction is worst case 1 network roundtrip, best case (returning user) 0 roundtrips - Anti-filtering baked in. Quic reveals almost nothing for middleboxes to filter on. There is not yet an accepted solution for encrypting the target server name (SSL SNI) but that's still being worked on AFAIK - "Modern" congestion control approach, where "modern" means "fuck any TCP connections sharing the link"