I ordered the voice keyer soon after my first activation and have been using it constantly since then. It made my activations much more enjoyable and less intrusive for the public on the summits.
I believe I did all the mods from this page. Did not do any measurements, but I get occasional comment about nice clear modulation.
I experienced RF imtrusion on UHF once (full power, FM, supplied rubber antenna) . Iadded a small clip-on ferrite to the mic lead after that, I hope it helps, I don’t use UHF often.