Are VPSs reliable? Couldn't someone else's application crash my server?
Virtual Private Servers are private, isolated, environments. You can rest assured that your server and your data will not be affected by other users' code. This benefit is especially important when mission critical web applications are being deployed.
You can easily back up both your data and your applications. You can essentially save the 'state' of your VPS and, in turn, guarantee reliable services to your clients.