[SoundsGood]

I don't really mind it especially considering it's completely free. If your host it windows (as it sounds) then you might want to check out VMWare Player.

[kezimo]

Good for the most part, other than a few incompatibilities with its emulated CPU architecture not supporting some encryption stuff.

[hunky]

I am also a Virtual Box user for long time.

Mainly I use it for web development.

Simple CentOS installation & then a LAMP stack to start developing, trying out different things before finally implementing that in my live website.

Its free & its really useful.

Thanks.

[Bripaticus]

I write software for a living.  I have done extensive Java development in the years past and I am currently developing some rather complex .NET applications.  I appreciate being able to create a virtual environment that I can use to simulate an end user's experience.  I have used both VMWare's VMPlayer and VirtualBox to achieve this.  I can honestly say that I believe they are both excellent options.  I do think that VMPlayer looks like a more polished product.

[dels]

I think for learning, development and experimentation VirtualBox is a great product, and in my experience it has a much better compatibility with OVA appliances than VMWare.
However, if you've going down the serving / hosting route, then'll you'll probably end up using VMWares ESXi server so it may pay to stick with VMPlayer or VMWorkstation.