The UI is horrible, very skeuomorphic, there are lingering bugs which they handwave away, there is no real "manual" though there are a hodgepodge of very poorly detailed instructions, but overall the Soundtower editors work.
I find their librarian functionality acceptable but the UI makes it incredibly easy to accidentally overwrite presets on your synth and - again, due to a lack of even basic thoroughness in their instructions - it's almost impossible to understand how it's best meant to be used. I personally don't bother with it much anymore, and I generally regret I bought it, but it does make programming the gated sequencer possible, as I find the on-synth screen nearly unusable for most functions.