I ran a curl test and noticed that the TCP connect time is where things are getting hung up, taking over 80 seconds! Does anyone know if this is indicative of deliberate rate limiting or just a bad peering connection?
Possibly neither, that is, there are many possible reasons.
for example, stateful firewalls can only track a certain number of connections. If you don't have a public IP, or if they are trying to protect you, it may be necessary to wait for a connection resource to come available. Connections are generally expensive, different from data transfer, for these and other reasons, such as port starvation, syn flood defenses inappropriately targeting you, so many others.
If it takes 80 seconds to TCP connect, something is pretty wrong.
tcpdump / wireshark would likely show lots of retransmits. Traceroute/mtr may give you an idea of where the loss starts. If you can find servers on similar hosting, you can get some idea of if it's targetted or not.
for example, stateful firewalls can only track a certain number of connections. If you don't have a public IP, or if they are trying to protect you, it may be necessary to wait for a connection resource to come available. Connections are generally expensive, different from data transfer, for these and other reasons, such as port starvation, syn flood defenses inappropriately targeting you, so many others.