The choice to go with Dash Charge instead of Qualcomm's Quick Charge 3 is rather disappointing which severely limits an otherwise great feature that many flagship phones are starting to offer. Other than that This phone really seems tough to beat if you're staying off of a provider contract.
OP made an interesting design choice to not implement the Qualcomm Quick Charge feature. According to their documentation (or AMA, or whatever), they chose a different technical solution to accomplish the same goal and have a few pros/cons for why they did Dash over QC.
QC gets more power to a phone by increasing the voltage supplied to the device at a standard 1.5A. This means that all phones that implement QC must also include circuitry inside the phone to step the voltage down from the 6-12V provided by the charger to the 5V normally expected by the phone. The advantage to this is that almost all existing cables can carry this extra voltage, so as long as the phone and charger are compatible, things will work. The downside is that the step-down circuitry generates a lot of heat, so your phone will heat up significantly while being charged.
Dash implements things a bit differently in that it uses a higher current at 5V to achieve the same power delivery. Instead of the normal 1.2-2.4A charger, Dash uses a 3-4A output at 5V. This means the overall power delivery compared to QC is almost the same, but the increase in current requires more robust cables. There's also no voltage step-down, so the phone doesn't have to take on the extra heat generated by that part. Finally, the control circuitry for Dash was moved from the phone to the power brick itself, further reducing heat in the phone while charging.
While heat isn't normally a problem if the phone is just sitting on your desk, it can come into play if you're charging and using the phone at the same time (gaming, GPS, etc.) It could introduce thermal throttling under certain conditions.
I can personally attest to the sheer speed of topping up my OP3 using Dash. I'll be at about 50% when I get home from work and need to go out for the evening. I'll plug my phone in to the Dash charger, spend about 20 minutes getting ready, and be ready to go with a phone that's 90%+ charged. It's pretty insane. On a recent trip to a tech conference, I actually stopped carrying around an external battery pack to top off my phone throughout the day, because I knew I could just plug in for 15 minutes and get enough power to last me through the rest of the day.