I have a large batch of L21 coming end Sept, I might be willing to let some go to grow my network with big miners who would like to try them. PM me for info. P.S their pricing includes PSU and its faster hash than l3+, you cannot compare the two.
520 vs 504 official hash rates, 900 watts vs 800 watts official rated power usages.
They're VERY close and definitely comparable units - much more so than the Bitmain S9 vs the Avalon 741 or any of the Bitfury-based machines that have been announced to date.
The big question is going to be "is the RELIABILITY better than recent Bitmain products" (which has been poor since the S7).
LKetc had a good track record there, but there haven't been enough BW.com units seen in the wilds to judge that yet.
The 100 min order thing though is a KILLER for most miners.