Along with price, they offer a huge variety of products, with a naming scheme that takes some serious study to comprehend -- which is the purpose of this page. And I won't say that I have mastered their scheme, but it is starting to come into focus for me. Their web page could be better. If it was, I would just offer links to their resources and this would be much more brief.
One article above says to forget trying to systematize the Arcteryx naming scheme and take each jacket on its own and look at the features offered. Cost, weight, type of fabric, number of pockets (and what pocket style), and type of hood. This is good advice. Pockets in the Alpha series tend to be "napoleon style" accessed across the jacket, while pockets in the Beta series tend to be the usual "hand warmer" pockets. You may get one or two pockets, and maybe an inside pocket too. They have three kinds of hoods. The simple clean "storm hood", the "drop hood" that includes a collar, and a "stow hood" that can be tucked into the collar. The Alpha series tends to stick with the "storm hood", but it makes its way into other models also.
Arcteryx uses an interesting set of symbols for the type of Gore-Tex fabric used in the shells. Something like N40p-X. Here is a quick explanation. The first letter "N" here indicates that the shell fabric is nylon, which is almost universal, but it could also be "P" for polyester. The number 40 indicates the denier or "heaviness" of the thread from which the fabric is woven. Bigger numbers are stouter. N40 is used on their lightweight pieces. The next letter (here a "p") indicates if the fabric is plain ("p") or ripstop ("r"). The optional suffix "-X" indicates that the fabric is extra tough (as I understand it) and is woven from thread with special tough properties.
The Alpha series all have cross pockets. All of the Beta and Zeta have hand warmer pockets. Here are some comments on pockets from a review of the Beta SV:
The zips are waterproof and positioned at your sides. This compared to the Alpha SV which has the primary zippers in the center upper chest. It's a compromise; the center design lets you easily access the pocket without throwing off your center of gravity, or sitting in a lift chair without disturbing your partners. The side zippers let you put your hands in your pockets to protect them from a chilly wind. All of the designs here work with a backpack.
The Beta SV line is made in China. Samples of Canadian-made Alpha SV and Chinese-made Beta SV showed no quality differences. Unless you work outdoors as a climbing guide or are going on a super epic multi-month expedition we feel the Alpha SV is overkill. Instead we would recommend something like the Editors' Choice winner Arc'teryx Alpha FL.
Note that the "AR" letters designate "all round". Also note that the only piece with a drop hood is the Beta AR.
Tom's hiking pages / tom@mmto.org