On the VM forum I read a fair few reports from people who had no issues on the tier below it, but than after upgrade it was slower than the lower tier, and they were blaming technical issues with the new docsis 3.1 channel, VM only add a single channel which seems a bit tight of them and only on the downstream so seem to be provisioning it with the absolutely minimal possible infrastructure. Those issues I dont think were congestion related though as the people appeared to be in areas that didnt have capacity faults.
The package seems hideously balanced, only 50mbit upload so 20:1 ratio. I remember when ignition started a blog on the ratio many years ago and VM eventually got to 3:1 ratio I think with their 30/10 package?