Give it another go after 100+ hrs of burn in, you'll be a believer then!
Edit: I also was not a huge fan of pairing Vega with Mojo. Best I heard it was out of a DX200 with Amp 3.
Seriously, burn in on DD's are a thing... even the manufacturer recommends it.
Side note: I'm really digging the mojo + vega combo, but I don't have anything "better" to compare it to. The mojo outclasses all my other portable gear. I have not been keeping up with the latest head-fi FOTM (my wallet thanks me)