Every point you make I can counter, I've been with them for years, have multiple VMs with them, find their support team fast, competent and courteous. DDOS is a problem for every ISP and every ISP customer.
During that time, Linode support tried ruthlessly to pass the buck and blame us and our clients, denying they had any major problems. Well, here we are and Linode DDoS attacks are STILL occurring on a regular basis, still making news, and they seem to do little about it in terms of a long-term solution. Whereas I have yet to have a single client suffer a Linode-scale DDoS on AWS or Azure at all after almost a half decade of using them.