I just installed the Hercules/Mose in my rather old LP12, and I wanted to add my positive comments to all the ones that others have posted here. I ordered from Edmund directly, and the unit arrived in California within a few days, so quickly it caught me completely off guard. Packing was terrific, the instructions were sparse but decipherable, and it was extremely easy to replace my Valhalla with the Hercules and Mose. Probably took me 45 minutes, working very slowly and carefully only because I'd never played around with the inside of my LP12, and I didn't want to mess things up. I initially connected the power switch the wrong way, but that was easy to figure out and correct.
First impressions are that this is a no-brainer upgrade. Nothing scientific in my observations, but the sound seems more clear, crisp, detailed, the speed seems more consistent (there was a bit of 'wobble' with the Valhalla), and everything works as it should. I'm finally getting the sound from my LP12 that I expected when I acquired it, without dealing with megabucks super-finicky Linn fanatics. This table has a Basik Plus arm and a Shure v15vxmr cartridge with Jico SAS stylus.
This is my second LP12; always thought these things were over-valued, but I got this one for very little $ along with a record collection (400 classical LPs and an LP12 with K9 cartridge for $600... not bad, and thank you very much Craigslist).
If you're sitting on an LP12 with Valhalla, this upgrade is highly recommended and very easy to implement. Edmund communicates quickly and responsibly. This was great all around!