I tried the Mojo yesterday at my local distributor. Its a nifty kit, and offers alot at its price point. At less than half the cost of the Hugo (more like a third of the hugo), it is certainly close in performance.
In terms of musicality and detail retrieval, while they are pretty even, the airiness, extension and soundstage of the hugo was SIGNIFICANTLY better. So to me (a hugo owner, so I may be/already am biased), I feel that while the Mojo is good, the Hugo has it beat.
I do think the Mojo will be a good addition to the Hugo's lineup, and for those considering the Hugo, but is unable to meet the price and mainly uses IEMs (like me), it is a good alternative. For those of us who have the Hugo though, the slight difference in presentation and huge difference in form factor may make it a good addition to what we already have.
Personally, I'm still considering getting the Mojo, but Canjam is just around the corner and I'm actually TRYING to save for it. The Mojo just put a spanner in my plans!
Just my 2 cents.