I really like the simplicity of the app as it does everything a normal user wants without bombarding you with values you have no clue of how to adjust.
Sadly this won't allow you to change any of the presets as some are terrible. The OGG Theora preset seems sensible but the G1 preset for example is terrible!! I converted the same small file with Miro and HandBreak (Using the iPhone preset with resolution and extension change): Miro's result is slightly smaller in size but has way worse video and especially worse audio quality than HandBreak's result.
The other problem I found was that it nearly never shows you the progress. Mostly it will just show you the striped bar but actually starts converting.
If the presets get some more tweaking and the small UI glitches get fixed, I think this could be a really great video converter.

I stopped using The Unarchiver 1.6 when I noticed, that it screws up the permissions of the files it extracts. So whenever you extracted something, the permissions were changed :/
Is this different with version 2.0?