You get a lot for your money in the Explorer2 - DAC with dedicated line-out and headphone amplifier. You also get their proprietary streaming technology, MQA, if that ever becomes mainstream - the Director does not have MQA. There's a lot of stuff "stuffed" into the small Explorer2 package. The Director is only a DAC, in a much larger package. And the MSRP was originally $700, so they had money to buy some better parts.
In my opinion, the Director sounds just a little bit better than the Explorer2. For those people who already own a pre-amp/amp or headphone amplifier, and are planning to use the DAC only at home, it makes sense to pay the extra $50 for the Director. It was a much harder sell when it was $700. Compared with the Schiit, well - at that point, I think you have to listen to it with your own ears. I have done back-to-back listening (I own both) and found there were more micro-details on the Schiit Bifrost Uber and more soundstage on the Meridian Director.
To put DACs in perspective, I recently did a comparison between 4 different headphone amplifiers, using the same headphone and the Explorer2 as my DAC. The Explorer2 has such a huge soundstage, I felt it made the comparisons between the amplifiers simpler. At the end of the comparison, I put the "winner" amplifier on my desk and plugged it into my Schiit Bifrost Uber. While I was blown away by the sound of my new favorite amplifier, during the comparison and while using the Explorer2, the difference now back on my desk with the Bifrost wasn't that much.
Explorer2 is a good DAC with other features. Director is a better DAC, but only a DAC. Schiit Bifrost Uber just sounds different, but I would not classify it as better. And I would recommend giving them all a listen - reading through other threads, there are some people who say the Schiit Modi 2 Uber sounds very close to the Schiit Bifrost Uber