Mojo is considered one of the best bang for buck for overall DAC and portable DAC at its price range. Considering you get 32 bit 768 KHz PCM and Quad DSD decoding, a custom DAC implementation + a portable battery for HiFi listening on the go, it's a no brainer.
However, if you need one of the top DACs (really overkill for a Q701, but this would make your future HP shine at best) at your max $1000 budget, the Matrix X-Sabre which uses the flagship ESS Sabre 9018S (the same exact DAC found on the Sennheiser Orpheus HEV1060) is your best bet.
If you need impressions against its competitors at the same price range, see this thread http://www.head-fi.org/t/650686/matrix-x-sabre-dac-review-and-impression-thread
BTW, both DACs are generally considered on the warm side of the neutral which is much better for the analytical nature of the Q701s
Edited by theveterans - 2/10/16 at 7:18pm