Just received my L300LE and 353x in black from Headamp (using this with an OL DAC with RCA-in listening via Google Play Music [haters please feel free to hate]). I'm upgrading from an SRM-1/MK-2 with Lambda Pros. The difference is clear -- these are smoother and more detailed, and voices in particular sound even more realistic (I feel like I've moved from the rear of the orchestra to the front center -- perfect). It's easier to place different instruments if listening to jazz, and the soundstage is similar to the Lambda Pros (which is to say, really big). The bass is tighter and punchier, though I detect a bit less rumble at verrry low frequencies (e.g., in Daft Punk's "Doin' it Right", there's a bit less rumble at the intro).
Notably, this isn't a comment on vanilla L300's, but as far as I know, they don't have a thread yet (sorry, mods, if I'm wrong).
I briefly tried normal L300s beside L700s a couple years ago, and the difference I remembered between them was mostly a smoothness gap, with the L700s coming out on top but not justifying the price in my mind. I can't effectively compare the L300LE to those two (and it's been awhile), but for ~$1,800, this setup (OL DAC, SRM-353x, SR-L300LE) is really damn good, and probably end-game for me. Plus everything is nicely designed with that sweet, sweet gold foil logo that I'm a sucker for and reminds me of the glory days of premium Japanese electronics.