OK, tonight I took the time to test the new beta of mGalaxy. I must admit I'm pretty damn
amazed how feature packed this version has become compared to the 3.0.
Configuring mGalaxy was a breeze. Just remember to run mGalaxy_Runway.exe before you start the frontend itself. Everything is quite straight forward except the fact that there's no possibility to choose another extension besides .zip . I know that this was intentionally left for us beta testers to find out

<Ext selected="1">
<Suf id="0" value=".zip" />
</Ext>
Just add the following <Suf id="1" value=".7z" /> (change ".7z" to your roms extension, leave the quotes) so it looks like this:
<Ext selected="1">
<Suf id="0" value=".zip" />
<Suf id="1" value=".7z" />
</Ext>
Remember, if you want to add multiple file extensions, every next row has to have the id part changed to a next number (autovalue)
Save the file, open the mGalaxy_Runway.exe and the extension should be visible for you... you're ready to go

* thing to consider before the full release: Maybe it would be useful to ask the user whether to run the mGalaxy_Runway.exe after the installer finishes.
For now I tested mGalaxy with MAME only but feature tests with various platforms will be carried out ASAP.
Another thing to consider for the final version is to add the ability to run a windows shortcut or executable file. I think this is "a must" considering mGalaxy is now opened to other emus. For example, I have many windows - native classic remakes of games like Karate Champ, Space invaders which are remakes built to run natively on windows or any other arcade game worth taking your time

http://www.classic-retro-games.com/games-list.php
http://retroremakes.com/nostalgia/
About the snap files... you can find MAME snaps here : http://www.mameui.info/
These are perfectly synced with rom files.
Peace
Alan