If I were to give this a "test drive" and didn't like it, does it uninstall fairly easily?
It's not really a case of uninstalling it Tom, it's only a file which you can delete quite easily.
I'll give you my experience with HOSTS file, because only a short while ago, I'd never heard of them.
First time I tried using a HOSTS file, with no knowledge of what it was, therefore no mental image of where it resided, how to use it etc, I installed a HOSTS Manager.
I must have done something wrong, because my pc was screwed up big time. It was a bad introduction to HOSTS, so it went the same journey as some other stuff when I did a complete reinstall.
This time, I decided to do it manually, and it was a piece of cake to do.
I downloaded the MVPS HOSTS file. I then went to start > my computer > C: drive > windows > system 32 > drivers > etc (etc being a folder, and not meaning carry on from here on your own).
In that folder, you will probably already have a HOSTS file with very little in it. If you want to check, you can open a HOSTS file with notepad.
Rename the HOSTS file, if there's one there, to anything really, maybe HOSTS.old. Do this because you don't want two files of the same name in a folder.
Then you can simply move or copy the downloaded MVPS HOSTS file to that folder.
If you don't want it. Delete it and rename your HOSTS.old or whatever, back to HOSTS.
You'll find that the MVPS HOSTS file download includes a simple batch file (mvps.bat) that will rename the existing HOSTS file to HOSTS.MVP then copy the included updated HOSTS file to the proper location.
This is the dead simple way to do it, but by explaining the above, I hope I've given you a mental picture of what exactly is happening, and where. Plus, I got more satisfaction, and a better understanding, by doing it myself.
Hope this helps.
EDIT: Very important, and maybe someone else can confirm this. While using the HOSTS file I learned that you must disable in services DNS Client. Do this by Start > run, type services.msc, look for DNS Client, stop the service, and change it to manual by right clicking, select properties, and use the drop down menu, otherwise it will start up again. If you bin the HOSTS file, change it back.
If you don't do this, you will probably have serious problems connecting to the web.