I’ve been off-net for a little over 18 years now
While I have no firsthand experience of how VM is (they were still calling themselves NTL when I had them), my impression from reading what people say here is that the technology is fundamentally good but their investment in customer service is poor and their installation/maintenance staff are too few and overworked. So if you get a problem, it is more likely to go spectacularly wrong, but problems, or customer service fails, are by no means inevitable.