AFAIK, sun hoodies have been around quite awhile and mostly been used by fishermen and in other such sports. Before the hiker trend of sun hoodies, Columbia had their PFG fishing line with shirts and hoodies hikers adopted and used.
As a handsome well dressed fashonista fly fisherman I've been using the Columbia PFG shirts since the late 90s, i think i still have one or two battered ones around, they were before their time for comfort and protection, really hard to get hold of in the UK back then, but amazingly cheap in the states and a huge selection of colours. Columbia, like everyone else tinkered with the original and i don't care for them anymore, plus just about every other manufacturer has easily accessible versions these days.
I've changed to the Patagonia Sol Patrol, which although great for sitting afloat for 8 hours on an english reservoir in the sun, isn't that great as a hiking shirt. Id like it in a slightly thinner material for that, I also have the Patagonia tropic comfort sun hoody, but its also too thick a material for me to hike in (and very over sized).
For dedicated hiking sun shirts
I'm with the esteemed smelly weegie (well south of Perth) gentleman, I love the cormac hoody, i can find no fault with it and its so comfortable
Patagonia capilene cool daily hoody is a close second, i basically live in the non hoody versions, hard to get the hoody in the UK the last few years.
The OR echo is good, I like the material and weight, but i generate enough static to power a small city when wearing it, made the mistake of pulling a senchi alpha top over it once
Merino, still has its place for me, i have loads of the smart wool boxers which i like when I'm going to be away for a long time, and a few very thin tops, but it has absolutely no appeal as a sun hoody for me
what I've seen so far with Darwin's offerings, he seems to be re-inventing the wheel with his product lines, relying on his "fan base" to buy it or tell everyone its the next "thing", I used to really like him when he did hiking vids, but like most of the "youtubers", hiking content runs out and it becomes all about selling/recommending stuff that they have only just looked at for a day, i don't think I've seen any of them actually say, "this is p!sh, don't buy it"
anyway, sorry about the big post, bored at work
PS
did i ever mention i met Darwin on the EBC trail
, (seemed a nice enough lad, so i wish him every success in his business, although nothing I've seen from him is for me (so far).
Only got messner, Haze and edh to go for the full house