There are a lot of threads on this...you may not get a lot of responses...I would suggest searching your question on google first and see what launcher threads on forums pop up...that being said , Nova launcher is great and there are many more with free trials. I would suggest trying a few launchers that have free trial and see if you like them. Then you can purchase the launcher of your choice to get extra options within that launcher.
You will not lose your original launcher. It will be there when you choose to switch back to it. I would however suggest removing widgets from your original launcher if you chose a replacement launcher as widgets are always running. I'm not sure it would make a difference on battery life but it might.
Setting up a launcher for the first time can be time consuming depending on how much you like to customize.
There are launchers out there that will even let you copy others set ups by just clicking install and it will install all apps for the themes, icon, widgets involved in that theme set up...I think Buzz launcher may be one of these types of launchers.
You can also look at the sticky above for home pages and themes...most will let you know what they are using.
Good luck and do this when you have some time as you will get sucked in and not want to stop...have fun.