I actually felt Beta 3 connectivity was quite good...
As for MP, been playing today without a hitch for the most part, and it's been an absolute blast. Connections to games have been rather good (and far better than Day 0, Day 1).
GPG/Stardock deserves its fair share of the blame for the condition of the netcode on release, and Brad's already noted that he's gotten his helping of humble pie. The blame needs to be kept in check by other conditions that are not merely finger-pointing, namely the early release and, more importantly, the high amount of pirate traffic (see the Kotaku article).