I think the relevant part of the review is that the Mitros was compared to the 580EX II, and IMO you'd need a very very good reason not to get into either 600EX-RTs or their Yongnuo clones.
Well you can't get into the Yongnuo clones, because they don't make them.
The Mitros+ is comparable to the 600-EX-RT, but the Mitros, like the one tested, is comparable to the 580EX II as it does not have radio. At $399.95 the Mitros+ is too close to the 600-EX-RT at $445 to convince many, the Mitros, at $299.95 is closer to a secondhand 580EX II if you don't want radio.
I have a couple of mitros + and so far they are super reliable however with eneloops they recycle noticably slower than the canons, for me this is not a huge deal but it has caught me out a couple of times. I went with the mitros because i am already heavily invested in phottix odins with 580s so it was a no brainer.
the other annoyance with the mitros is the head does not click into set positions this can be a bit annoying
However if i had no speedlights or a minimal investment I would just forget everything else and go with 600RTs and an ST-E3
Do you have a guide number chart for the Phottix Mitros+? I can't seem to find one online either for the Mitros or Mitros+. Canon's 600ex-RT has a table of guide numbers for each zoom setting in the user manual.
Eos: 1Ds-III, 5D-III, 6D, 60D | Canon EF: TSE-24L-II, 16-35L-II, 24L-II, 35L, 40STM, 100f/2.8, 135L | Wishlist: TSE-17L, 200f/2L
Tamron: 24-70VC, 70-200VC, 150-600VC | Samyang: 8mm-T3.8, 14mm-T3.1
Crazy Ideas: TSE-90L-II, 40f/1, 100f/1.4, 35-85f/2, 100-300f/4_1.4xInt, 500f/5.6_1.4xInt