Freenet is faster than that in aggregate, total node throughput can be in the 150-250KB/s range even if single requests are, as you say, potentially in the tens

Freenet is faster than that in aggregate, total node throughput can be in the 150-250KB/s range even if single requests are, as you say, potentially in the tens of KB/s. File transfers can be fast, static webpages can be loaded reasonably quickly if they are popular (in the sense of being frequently accessed by users). Big security downside is that in the purely opennet configuration, your peer nodes are both untrusted strangers AND your own traffic is visible to them. There is NO "onion" effect going on, just reliance on the possibility that any traffic a peer node observes from your node is not necessarily YOUR traffic as all nodes are also routing requests for other nodes.