Hetzner has a very bespoke setup. Their DC's mostly run on their own renewable power sources and have been refined to the limit, combined with recycling hardware for longer periods, not using server chassis or off the shelf components, and a highly bespoke racking setup and it makes for mass scale at a very low cost.

OVH has a similar setup but is way more diversified into other product lines. I'd personally never touch them after the fire that they never bothered to explain to those of us affected by it. With the amount of downtime they had there it made it very clear that their ability to recover a situation - any situation is crap.