On the subject of the Baggs Element UST, I've actually made direct-from-pickup recording tests between the Element UST and David Enke's "Open To Source Sensors" UST. The same guitar was used for both sets of recordings as the OTSS UST installs the same way as the Element (threaded up through a slanted hole in the bridgeplate). It was an easy swap as David connected a mini-plug to the UST lead so that I could plug it into the guitar's "barn door" style Baggs preamp.
The Element UST is the first sample in each playing style pairing. Both samples in each pair were normalized for the same peak level.
https://soundcloud.com/guitaniac/pic...-baggs-element
On the subject of the Baggs Element and UST/mic pairings, I do think that Aaron Short's review of the MiSi Trio Air is worth consideration. The Trio AIr has worked for Aaron in a noisy solo act setting, and of course the mic level can be reduced or removed for higher feedback-free gain.
https://youtu.be/MSQujy1u-3M