Everyone wanted to be on Softlayer for a time. It was THE hosting provider. I don’t know if they where any good, but the got great press coverage.
Two years ago I had to help a customer debug some weird nginx behaviour, resulting in their traffic spiking at ten times the expected rate. The IBM/Softlayer VPN required that I used Internet Explorer, but it still failed to work. We spend three month with IBM and IBM Cloud consultants to make it NOT work.
IBM destroy everything it buys. They have POWER, their mainframes and associated software left. How that keeps them afloat is a mystery.
Softlayer was solid at providing colo and dedicated servers. But they were never really architected with the cloud in mind. The pivot to cloud came later on. I always wonder why IBM didn't buy a provider like Linode.
Softlayer had the idea of API-driven bare-metal server hosting (as opposed to ticket-driven or phone-call-driven) early on, which was a big differentiator for a while. But AWS came along with an even more extreme version of API-driven hosting and they never caught up.
As an example, most network or server changes you made through the API resulted in an automated email saying your sales representative would be in touch about your order, followed a minute later by an automated email saying the change was done at $0 charge.