Oh Danner, how you've changed my life...Gone are those treacherous days commenced by the donning of Standard Issue footkillers...Gone are the massive blisters that make me question the matter of life itself...Gone is my paralyzing fear of walking, running, or rucking for miles that seemingly never end.I have owned two pairs of Tachyons. I must have put somewhere around 300 harddddd miles on my first pair and have since put somewhere around 100 on my new pair. I have worn these things for long-distance runs, even longer distance competition rucks (the best boots you could ever have for the Norwegian FM), lengthy FTX's, airborne school, SERE school, and even at my wedding!...just kidding, nobody loves me :,( ...But I digress. My first pair wasn't even broken or anything -- I just lost them when I moved. I CANNOT recommend these boots enough. I have recommended them to every friend, mentee, and random passerby I've ever had/encountered. I've convinced so many people to buy these boots that Danner should pay me a commission.The pros are as follows:+ SUPER lightweight. I have a pair of Hoka's and I'm pretty sure my Tachyons weigh less.+ SUPER breathable: Don't you HATE wet feet? Whether you're a super-sweater like me, or just always seem to find a day-ruining puddle wherever you go, these boots will let you get dry quickly. Since they're so thing, they can't really retain water AND are excellent at allowing your feet to offgas a lot of that built up heat.+ SUPER durable: As I mentioned above, these bad boys have yet to fail me. I'm not a mega-hooah, so I haven't gone through RANGER SCHOOL or selection, but these things have held up to everything that I've thrown at them. Even after 300+ miles they were still serviceable, if not a little beat up.Cons:+ Not a lot of ankle support: I'm a big dude, standing 6'4 and 220-pounds. I don't have great ankles, but I've never had an issue with these. I'm only including this as a con because some of my weaker-ankled friends have mentioned that the Tachyons are bested by Garmont Bifidas in the uneven terrain of the woods. But seriously, I've done airborne jumps with these things with no issue; I've also crawled through all the inhospitable woods of the Great American Midwest and the Dirty South without any problems. I just wanted to include the disclaimer from my friends.+ Not a lot of heat retention: As I mentioned above, these boots are pretty thin, especially in the uppers. While this makes them great for heat dissipation and rapid drying, it also makes them a mediocre choice for the cold. If you're frequently operating in a wicked cold environment, you'll probably want something like the Rocky S2V's -- which are practically ovens.+ Iffy insoles: The insoles included in these boots aren't great. I did a quick swap with some Dr. Scholl's inserts from Walmart and BAM! the boots were perfect. I wish they'd have slightly better stock insoles, but nothing's ever perfect.If you're looking for THE BEST pair of ruck run boots, the Tachyons are your boots! If you're looking for a good pair of cool-footed garrison boots, the Tachyons are your boots! If you're working in wet, hot conditions, the Tachyons are your boots! If you like looking cool and feeling good, the Tachyons are your boots! If you...get the picture, these are THE boots for you.(PLZ sponsor me, Danner. I'll do any sport thingy you want for a free pair of Tachyons).