I have been using this service for over 10 years now, since my first computer was installed from them in 2005 - they are very reliable with fast friendly support, always willing to help you out if something goes wrong (which it usually does). They do not provide any guarantees about uptime or performance but as long as your hardware isn't faulty then there's no reason why things should go wrong. There really aren't many downsides that i can think of other than perhaps too expensive compared to some others similar providers? The price tag seems high at times so check what else is available before making up your mind! We use a number of computers running different operating systems across our office including Windows 7/8 & Linux desktops, iOS devices (iPad) and Android phones etc.