Personally, I own the E10 and just ordered the HifimeDIY to compare them (via the E10's line out and the HFMDIY directly to a separate amp). Since I don't have the latter yet, I can only refer you to other sources.
Tech sheets on both DACs:
The Wolfson WM8740:
The ESS ES9023:
Have a look at this post from someone who owns both the E17 and an iteration of the HifimeDIY (he doesn't say which, though his comment suggests it's the 24/96-capable model): (http://www.head-fi.org/t/651769/fiio-x3-thread-full-review-http-www-head-fi-org-t-663600-impression-fiio-x3-high-fi-low-price/1410#post_9501113):
I have FIIO E17 (based on WM8740) and 2 ES9023-based DACs - ODAC and Hifimediy.
Both of them sound superior to FIIO E17.
ES9023 isn't even that power hungry - ODAC works fine powered by my cellphone.
It's very cheap too - hifimediy has a new 30$ USB DAC based on it.
It's quite affordable for a DAP that costs hundreds of dollars.
BTW, the same question can be addressed to FIIO's DAC/AMPs - why no ES9023?
WM8740 is not a top Wolfson DAC for a while - WM8741 and WM8742 replaced it.
Ben prefers the HifimeDIY to his E17 (which uses the same DAC as the E10 but is said to sound slightly better).
The ODAC uses the ES9023. On the other hand, the Astel&Kern AK100 uses the WM8740.
Keep in mind that the E10 includes an amp with the Wolfson, whereas the HifiMeDiy Sabre USB DAC is essentially a DAC chip attached to a USB receiver chip and cable.
If you won't be using a dedicated amp, you might want to opt for the E10.
Edited by scrypt - 8/7/13 at 3:07am