Yes, there is more discussion of the 508 over at Audio shark, as Charles stated. In fact, some of the folks there actually heard the 508 compared to both the 518 and 219 and posted some very interesting impressions. It is an informative and insightful discussion. I've had mine several months now and don't think I could love it any more. I think Wig loves his just as much, and we have both enjoyed quite a few awesome amps in our systems over the years, for whatever that may be worth to you. The 508 is built like a tank and sounds magical, especially with upgraded tubes. I love the looks of it, too. I would imagine any of those three LM amps would sound fantastic with the Double Impacts, speaking of which--mine arrived today, two days ahead of schedule!
I have them installed now and have been listening for less than an hour, so I will reserve judgment for a bit. I do like what I am hearing so far.--honestly, I am shocked by how good they sound right out of the box. I will need to play around with placement some and get at least 40-50 hours on them before saying too much. When I get to 100 hours, I will put the Ulysses back in and then we will see what's what. This is going to be a LOT of fun. The DI are clearly very impressive speakers. This going to be some tussle between two great sets of speakers!