From their own web-site:
"In spite of the low price, quality has never been compromised. All servers are of the best Hewlett-Packard quality with redundant power supplies, mirrored SCSI disks with daily external tape-backup.
The systems are placed in a private server room at Interxion in Denmark. The server room has redundant power circuits, battery backup, diesel generators and a Vesda (Very early Smoke Detection Alarm) smoke alarm system.
Our backbone is fibre-based with redundant infrastructure. The total bandwidth is at present 2 x 1 Gigabit multi-homed attached and connected to 3 international carriers, Global Crossing, Deutsche Telecom and Level3, in addition to Danish Internet eXchange.
Servers, server rooms and the bandwidth are monitored around the clock, 365 days a year."
And this:
“B-one’s data centre is located at Interxion, which offers world-class server room facilities and guarantees 99.999% uptime. See www.interxion.com for further information.”
Saying that, I’ve experienced at least one day (or at least a few hours) of downtime with them in the past at one point or another. We’ve used them for about 2 1/2 years.