What is the difference between managed and unmanaged VPS for hosting? And Which is recommended?
A "managed" system typically means that the hosting provider takes some responsibility for ensuring that everything is configured and functioning properly. This may include installation services, monitoring, regular updates, configuration assistance, and so forth. An "unmanaged" systems means you're on your own.
Which is is recommended depends entirely on your level of experience, comfort, and free time.
The term managed really is quite a bit different from vendor to vendor. For example - a Children's Publication organization - now a client of ours who we are helping rebuild their entire website is using a very well known "Fanatical Support" company who in short stated to us earlier this week...
"We managed it but refuse to give any SLA or warranty once the customer logs in via SSH..."
So - this vendor gives a 100% guarantee until you actually put a site on your server or vps. Sound's crazy does it not?
There are great organizations like Media Temple (who advertises here in the ServerFault site) as well as BuckEye Colo and folks like VPS.net who will do more than just the basic management.
If you were to take a look @ some providers they actually have levels of "support" and "management."
I hope that helps - Larsks is dead on - but the added perspective I thought may help you just a little.
My suggestion is to support those companies that advertise here - as that will help keep conversations within the ServerFault and StackOverFlow community keep happening.