I found this link earlier today. Haven't seen or used the new Arc'teryx Acto. But I agree with much of what the author, Jason Kruk has written here. Different combos, looking for same results.
"Arc snuck this beauty onto the new fall '11 website without any fanfare. They should have made a bigger deal, though, it's the best thing to happen to softshell jackets ever. I had given up on softshells for my upper layers. The once game-changing Gamma Jacket hadn't received an update in far too long. The material was too heavy to justify using on a serious alpine climb. It didn't breath particularly well, either. I would sweat like a pig while climbing or working hard on the up while ski touring. I switched my systems to a lightweight fleece layer like the Delta LT and a Gore piece on top like the Alpha LT or new FL"
Enough said that I will be checking the Acto out asap.
more from a little digging on the Acto
I thought the Acto sounded good enough that three days after posting this blog I had one here to play with. During the winter of 2008/9 I had a very similar fleece jacket from Arcteryx that another Arcteryx sponsored climber used and promoted. Price was similar but mine was without a hood. It did breath well, and shed water fairly well even in our wet and rainy climate here in the NW.
It is a very similar thickness to the Acto gridded fleece. But it had better cuff detailing and a more trim, more athletic fit. It was made to be used as a mid layer piece as well. Soft grid pattern fleece on the inside and a hard finished soft shell on the outside that other layers moved freely on.
I don't remember the name of that specific piece from Arcteryx for sure but I think it was an earlier version of the Epsilon AR Jacket. Arcteryx lists the Epsilon and several others as "hard fleece".
After seeing the Acto I can say I am a little disappointed on the fit and detailing on this $300 garment. And like my previous garment before it, I am not sure I can find a place in my clothing system, either climbing or skiing, that the Acto makes much sense compared to others I now use.
If you can take a look at one I would to make up your own mind. I think part of the problem is we all seem to want a lwt version of the Gamma MX. The Acto promises a lot and doesn't do much for me @ $300. The Gamma MX seems a steal at $350 by comparison as does the Epsilon SV Hoody @ $225.
I haven't even bothered to look at what else is available from other manufactures for similar style garments. But may be you should if the Acto sounds enticing.