Welcome to the forum
You will be happy to know (depending on your unit spec) that not only can you have more than one vector distro, you can have several distros on one drive (naturally depending on the drive size) and choose how you want to boot them.
Often this is achieved via the bootloader(ie:grub or lilo) which on boot gives you a choice of which OS you want to boot or defaults to one after a time out. you can also run many linux from a cd/dvd or usb stick and choose via the computer boot menu or bios settings. thus needing no hard drive or allowing play with other systems without tampering with your installed Vector OS.
The standard release of Vector usually has more than one desktop environment and you can choose which you want to play with or use at login by clicking the session menu and selecting it.
The default xfce is very easy to customize and the fluxbox desktop is also customizable and very good for learning things as it can require manual edits to customize where xfce is more automated. And then there is awesome. Alternatively there are bigger and smaller versions of the OS to choose from. Here are my current xfce and fluxbox desktops on the standard version, simple changes that offer a custom look and feel, you will find a greater freedom compared to windows and OSX where the desktop is concerned.https://www.dropbox.com/s/dmrvk1xsh4wehog/XfceRC1.pnghttps://www.dropbox.com/s/fagftyk5g2olkkh/FluxboxRC1.png
The defaults offer a great selection of applications for most users and you can easily add additional application with the gslapt package manager. the first time you use gslapt you will need to click the update button to insure you have the latest additions to the repositories. do not confuse the "update" button with the "add all updates" button. they are two very different things
You can also find additional desktop environments in the package manager should you prefer alternatives to the included ones. or Vector includes tools to build what you like if you are up to the task.
I find Vector quick and stable and a great out of box experience especially for those who want to learn. Not because it requires anything in particular rather the facility is there to do as you please in most cases. The forum is naturally a wealth of information in addition to your internet searches for information and check out stretchedthins video tutorials, I think there is a link on the desktop.