I just want to say that after about six months, I'm really happy with my Modi. I've not compared it to a Bifrost or anything else and I run it through powered speakers so there's no need for an amp. But in terms of bang for the buck, the Modi is great. I picked up a second one used for $70. That's great value.
I'm not super picky. My speakers (Audioengine A5+) sound great running MOG through my Macbook with the Modi. I'm sure there are some who would not be satisfied with such a basic setup. But it seems a matter of diminishing returns. To improve the sound, one has to invest a lot of money for small, incremental improvements. A Bifrost might improve the sound quality a bit. I don't know how to quantify such things but let's say 5 percent. To get that small improvement, I'd have to pay four times as much for my DAC. Thus, I just put such things out of my mind and enjoy what I've got.
Before long, the Modi will be surpassed by better products that cost even less. That's inevitable. So I'll wait to upgrade until I can do so at a cost that doesn't break the bank.