The main disadvantage of the colo servers I administrate is the lack of flexibility for periods of hours to days. We use ~50 fairly high performance (RAM, CPU,

The main disadvantage of the colo servers I administrate is the lack of flexibility for periods of hours to days. We use ~50 fairly high performance (RAM, CPU, disc) servers pretty much continuously, so the savings compared to AWS etc are considerable. Every couple of years there's a software upgrade required, and it would be convenient to have another 50 servers to use during the transition, just for a few days. Compared to AWS prices, we can easily justify keeping some old servers around to help with this sort of thing. A managed server company (Hetzner etc) would be somewhere in-between; presumably able to rent us 50 extra machines for the duration, but (last time we checked) still more expensive than managing the servers ourselves.