Satson has more features (trim control, nice filters). That said, if it models a VU meter well then I'm sure it's fine. *ETA* Just reread the ad for that plugin, it has a trim control too. So just the filters (and the console stuff if you're using that) are the difference from Satson.
You can also use Nebula's meters for VU (which have changed a bunch in the last several months), there are some skins with good VU meters already and I'm sure more will be on the way now that the technology is there.
I don't have the new meter (yet) so I can't comment about the behavior etc, but an "external" VU meter is not effected by the way certain presets are padded. It should give you accurate VU levels regardless of the presets you are using (some measurements in the following link: http://www.acustica-audio.com/forum/ind ... pic#p13175 )
I hope the VUMT will include a user-defined peak/clip meter in the future. Very useful (once implemented) because it gives you a way to set your "real" headroom while using Nebula.