when I was at he.net, the outage reports were all about ATS failures and the like. I mean, switching that much power is serious busines... a lot of the cut-rate datacenters I've been at mostly had power outages when their switching equipment failed, even when they had decent UPS and generator capacity.
Personally, if I were building a cut-rate datacenter with used/unreliable power equipment? I'd build two parallel power systems to each rack. Each customer would get two independent power feeds (and stern warnings to not use more than 80% of one circuit total) (I mean, while new kit is super expensive, used power conditioning equipment can be had on the cheap if you are in the right place at the right time.)
Then, so long as customer buys dual PSU equpment (or their own small ATS, and I've had better luck with 20a automatic transfers switches) they'd be fine.
Of course, I've never gotten the chance to try, (well, I did kind of have a chance once, but I kind of blew it for non-technical reasons before I got to build out a power system of my liking.) so maybe I'm missing something. Maybe the electrician work is more expensive than I think or something.
I'm a little surprised that anyone with any scale still uses he.net for physical hosting; Last time I tried to negotiate with them, at my scale (20kw) they essentially charged $400 for every 1.4kw, (and they gave you a rack with that 1.4kw) which is kindof a terrible deal compared to higher density co-location providers like coresite or BAIS, where your racks are closer to 5kw each, but that rack usually comes closer to $1300 or so.
(Most rackmount servers are power-dense enough to eat 5Kw of power in 42u, with some space over)
This means that after your first few servers, the higher end datacenters are actually way cheaper.
I mean, don't get me wrong, I think he.net bandwidth is a great part of anyone's BGP mix, and I think that he.net hosting is the best deal around if you only have 1.4kw of power and want your own rack (often they will sell you your own rack, 1.44kw of power, and a nice unmetered gigE pipe for $500 a month, which is a killer deal for a rack and a gig. But it's kinda terrible if you are using serious amounts of power)
On the other hand, the he.net remote hands are... some of the best. I mean, they are remote hands and super junior people, with all the problems that come with that, (remote hands is, as far as I can tell, a junior sort of job many places I've seen.) but they are on site, on the ball, and every time I called in, they were right there, and it's free.
Last time I called coresite for remote hands, they said they would charge me $200/hr... reasonable, I suppose, for getting someone junior-ish out of bed, but they had to page the person, and their person still wasn't there two hours later when I was able to arrive.