What opinions do people have out there about Webmin vs Plesk? Any positive / negative experiences to speak of?

They're both good, however you're comparing apples with oranges.

Webmin: its a sysadmin tool, yes you can run a webhost usng it, but you can similarly run a webhost by editing conf files in vi.

Plesk: its a control panel designed for webhosting, add a user, he gets a new virtual host entry, added to the ftp users, email account setup etc etc. With webmin, you'd have to do each of these things manually.

I'll warn you now, my plesk experience has left me sour, i thought i would get away with webmin until i decided that plesk was the best solution and now it doesnt even install properly and im down a couple of hundred dollars that im sure other open source control panels would have plesk beat with a stick

digital_soul18, you'll be worng. I've used a few control panels, and the commercial ones beat all the free ones in terms of functionality and features. Plesk is a good CP, if you've had problems installing it, the issue isn't with Plesk. I suggest you contact SWswoft support for help.

All CPs have 'problems' installing. Nearly all of them (including the free ones) say you must install on a bare OS install - if ou have other things installed previously, they don't want to know - wipe the OS and start again is the answer to install problems. This is because they all use their own selection of servers, e.g. plesk uses qmail, ISPconfig uses Postfix, DirectAdmin used Exim. If you want to use sendmail, none of the above will be happy, and will have difficulties installing.

The free CPs are good, but they are still up and coming.