I got my E17 in and think i'll probably keep it. I do somewhat wish I just had gotten the E9k though. Figured i'd post some impressions since it's all with the Q701 only so far.
I only listened to it as a DAC+Amp for 10 minutes. Sounds pretty good but can't really say much else yet.
I'm using it mainly as a backup DAC with L7. First thing I noticed is that it's slightly warmer and fuller sounding than the Modi. Now this doesn't mean it's better than the Modi, just with some nice coloration and that's OK. Still flat though. I'd say the E17 is obviously more musical in most cases (for me). The soundstage on the E17 is a lot smaller and less airy and the sound not as clear (or so it seems). I usually get this when something is warmer sounding.
The mids of the Modi sound more flat and almost relaxed in comparison. Really harsh, bright and annoying Jpop sounds noticeably worse on the E17. It's not too bad though. To me the Modi sounds perfectly flat to my ears (again, I know they both measure flat, but often sometimes things sound differently).
The bass sounds a bit better on the E17 for some reason. It just sounds not as present on the Modi. Probably impossible.
My amp has two inputs so I can match the volume and switch between the Modi and E17. Sometimes I actually think i'm listening to the Modi and then realize it's actually the E17. There's not anything that jumps out at me that's like a night and day difference. The differences are greater than the ODAC vs Modi though.
The reason I wanted the E17 is that I'm a huge fan of my first Ipod. It's the Classic 3G with monochrome screen. Sounds amazing and has just a touch of warm. It uses a Wolfson DAC too and this sounds like that Ipod on steroids almost. The warmth (so far) isn't enough to ruin any headphone. Maybe some don't think the E17 is warm at all. It definitely is compared to the ODAC, Modi and my Ipod Touch 2G. I think the HRT MSII might be slightly warmer though.
Modi sounds better overall, but the E17 is pretty nice so far. I'll not know for sure until I try all my headphones with it. My Q701 actually isn't as good as my DJ100 and HD-650 for hearing the differences between equipment
To me the E17 definitely sounds better as a DAC than the E10 I had. Not sure how or why this is.
Luckily this sounds exactly like I expected! That almost never happens for me.