Disclaimer: I am no way associated with Audioquest, I bought the Dragonfly RED with my own money and this review reflect my honest opinion after 1 month of daily usage. I am more an audio enthusiast than an audiophile, so take this in consideration. Plus, English is not my native language and to write this review (my first one) took time and patience. Happy Reading!!!
 
 
Introduction:
The Audioquest Dragonfly RED (DFR from now) is the third incarnation of the classic Dragonfly that was introduced in 2012. There are big changes with the DFR, the major upgrade is the compatibility with all the iOS device. The internal DAC is upgraded too, we got a highly regarded ESS Sabre 9016 chip inside. The Power Output is set at 2,1 Volt, very good value for a tiny device like this, considering It will drain (just) 35 ma of power.
 
 
Build Quality and Accessories:
The product is very well built and comes in a very nice box, the unboxing was really a pleasure. The Red color is made of a glossy-shiny paint. In contrast the DFB (yes I got the DFB first, but I returned it) was matte finish with a different feel in the hand. All in all, The RED screams more quality, and It's more classy and I like it.
To store your precious Dragonfly RED, you got a nice leather case with the Dragonfly logo on it, also very nice touch.
 
 
 
 
Sound Quality With Various Headphones:
My previous DAC was The FIIO ALPEN and I was not very impressed to be honest. Of course the Amp section was very good, and with 3 gain stage, you can almost drive any headphone on the market with good results. On the DAC section I was a bit more sceptic, I really cannot spot much of a difference between my Macbook Air headphone out and the ALPEN. After some time and ear training, the difference was clear, the ALPEN was more warmer and a bit more open sounding, but again, not a night and day difference.
When I got the DFR I was impressed from the start. This device really unlock the true potential of your headphone. The results are stunning with easy and medium to drive headphone, and very good with hard to drive cans.
 
The first headphone I tested was the community favorite Audio-Technica M50x. The result was impressive. The M50x sounded almost like an open headphone, soundstage was dramatically improved in width with a better detail retrieval. Gone was the slightly boomy bass and the harshness in the treble, the sound was much more controlled and smooth. 
Usually I like to listen some Math-Rock, a genre with nice clean guitars and fast technical drums (check This Town Need Guns). The sound of the DFR was effortless, It can handle even the most busy part with almost no congestion, clean guitars sounded crystal clear, drums were life-like.
From this test I can say that the DFR is pretty natural and smooth sounding, you hear pretty much your headphone with very slight coloration. The M50x has a very refined driver inside that "scales" with better equipment.
 
 
 
 
 
 
Second Test was more hard: Sennheiser HD600
This headphone as many of you already know, is a 300 ohm impedance one. Not extremely hard to drive in my opinion, it can go pretty loud with a simple amplification. Of course to unlock the full potential a tube amp is recommended. 
Even with the HD600 the DFR in a word: Deliver!
For the first time I can use the HD600 with my Iphone with the DFR and get an amazing sound quality on the go. The maximum volume is still high and sound is very refined. With the Fiio Alpen the sound is a bit more bassier and veiled, the DFR is smooth but at the same time very clear. The hd600 is a mellow headphone with balanced sound, usually it doesn't have an immediate WOW factor because of the sound-signature. So I was not expecting the WOW factor with the DFR. What I got is a very pleasant smooth sound that impress mostly in long listening session. Do you like to rock-out quickly? No problem! The hd600 is not a sleepy cans and can handle rock and metal very good, and so with the DFR.
All in all, nice pairing! 
 
Fostex T50 RP Mk3
The mk3's is planar magnetic headphone and hard to drive. I was expecting the same performance of the HD600 but it's not happening. Sure you can drive them with the DFR and sometimes I do, but I think the DFR is a bit short on power in this case. So the pairing is just average in my opinion. 
 
Various iem: Hifiman re400, Yamaha Eph100, Shure se215, Sennheiser IE80, Mee M6pro, Xiaomi Pistons 3. I will be short and sweet. These iem's are very simple to drive and the DFR really boost up the sound quality, I got no hiss. Highly Recommended.

 
 
 
Compared to other DACS:
Audioquest Dragonfly Black: As i said I got the DFB and I returned it. The main difference between the two is the Output power, the DFB is much less powerful and can drive only portable cans and iems in my opinion. It was struggling with my HD600 where the DFR is brilliant. The Sound-Signature is more bassier on the DFB - a bit like the Fiio Alpen, honestly I like less coloration so this is another point where the RED is superior. 
 
Fiio Alpen: It was my first DAC and It's a good one but not outstanding. It's more powerful in the amp section than the DFR but the DAC section is one league below. The DFR has more clarity and It's more balanced overall with a better soundstage.
 
 
Conclusions:
The DFR is a brilliant little DAC that can drive almost any headphone with awesome sound quality. For the first time (for me) it was obvious that I got a better sound. The sound-signature is very natural and smooth with amazing soundstage depth and overall clarity and detail retrival. It is impressive as a computer DAC alone, take the fact that you can hook the DFR to any Iphone and turn it in a Hi-FI DAP, that is killer dude! It's like to get 2 device in one. The only drawback for me is that I would love to drive my T50RP mk3 with it! Maybe the next Dragonfly will output 4 volt? I hope!
Kudos to Gordon Rankin and Audioquest for this magic little Dragonfly!
Ps: Don't try to connect it to your coffee machine, It won't work, I was kidding!