After reading the last 20 pages or so of this thread, I decided to pull the trigger on the Deckard and EL-8 (Open) headphones. Both were open box at my local Best Buy, paid $499 for each of them. I'm new to high-res audio, and my previous setup is HD600's fed via the Oppo HA2-SE. Since my ears aren't very experienced yet, I was having difficulty picking out the differences between the 2 setups. Then I finally found a few FLAC songs that I know very well and did a couple of hours of A/B testing, using only the EL-8 to isolate differences in the dac/amp combos. Now I get it....the bass is MUCH tighter on the Deckard, some songs come across as muddy on the Oppo. I'll be keeping both setups though, I'll just use the Oppo with my laptop when I'm at a client site and keep the Deckard for my desktop. I'm going to stick with the DAC in the Deckard for now, but I think I'll eventually upgrade it to something a little cleaner sounding. From the advice on this forum, I'll need to spend in the $1000 range to get an appreciable upgrade to the Deckard DAC, so that will have to wait a while.
The EL-8 to HD600 comparison is a little tougher, as I like them both. The EL-8 has more bass, but the HD600 is cleaner sounding overall. Not sure which one will end up as my main set. I have the Massdrop Fostex TH-X00 ordered, so that will be an interesting comparison next week.