I didn't own both at the same time, so I couldn't do a direct comparison but the L3000 arrived within 2 weeks after I sold the PS-1.
For build quality, the L3000 is hands down the winner. The PS-1 was pretty much the same cable and headband on the RS-1. I think it might have been a little more padding on top. Didn't feel like a $1400 headphone. The L3000 has a nice cable and beautiful leather cups and headband. Also has leather earpads which makes them more comfortable.
For sound, it's very close and more of a preference. The PS-1 has a more impressive sound on first listen because it hits harder. It's very dynamic. The issue is it can make songs sound similar. On softer songs, it can be too punchy. And the bass is more difficult to tame. On some systems, the bass is a little too strong. The rest of the sound is amazing. Very technical while staying fun.
The L3000 has a little bit thicker sound but with the DHA3000, it brightens up a little bit. The bass seems to go deeper and has more texture than the PS-1. The mids are probably close but not as liquidy or airy. They do have the Grado type sound in the mids and handle electric guitar great. I guess it's that twangy sound a lot of headphones gloss over. I'm sure the PS-1 is brighter but I don't have any problems with the L3000. For overall sound, I think the L3000 is more balance and has better soundstage with precise positions within a small area. The PS-1 had the best soundstage of the Grados before the GS1000 and PS1000 came along, but I don't care for them since they are too distance for my taste. But as far as sounding different for each type of song, the L3000 can sound relaxed when it needs to or thunderous when a song calls for it. It's probably slightly colored because everything is still is fun and enjoyable, which I think it a good thing. I also can listen to the L3000 for longer periods than the PS-1. Not sure if it was comfort or sound but after a couple hours, I'd have to take a break from the PS-1.
Now if I ever get a chance to hear these side by side, my opinions may change. I probably guess the PS-1 would win a quick side by side but it's extended listening that really counts.