I don't know what to make of the bad reviews you found, my personal experience has been great for several years now. Multiple products used, the occasional support ticket with quick response, and decent pricing.
Anecdote: I had my dedicated server suddenly go down because it overheated. Wouldn't come back to life. Two days after submitting a ticket and getting no input, the machine suddenly came back up without any explanation. A day later, I got a mail saying the motherboard was broken and got replaced. Overall it was a very unpleasant experience, but it's to be expected given the low price of Kimsufi.
It's good to know that this stuff happens with OVH. I'll make sure to stay far from them.
This thing happens with Kimsufi servers, a side brand of OVH for cheap dedicated servers. The real OVH servers are more expensive, but you get all the bells and whisles that come with a professional server hosting offer.
We've had very few hardware-related issues, a disk failing or a motherboard to be replaced. In all of those cases, the component were swapped promptly and we've been kept informed of the progress.
Where we're unhappy is with the network, especially with their vRack offering. Looking back at our production incidents of the past 6 months, about 50% of them were caused by some vRack problem where at the same time the public interfaces were up and running just fine.
We're generally happy with customer service, but we pay for VIP support and we speak French to OVH's support agents (I believe that the latter helps a lot).