Yep...non-subscribing players can do all of the content* and have access to every ability, skill, etc. There are a lot of costume options that are only in the cash shop, but there are also a lot that are available with in-game currency. too. Nothing that's exclusively in the cash shop can really be considered "buy to win," either.
* There are going to be more cash shop mission packs (currently only one, and it's truly excellent), but they won't be the only new content or even the majority thereof. Paid subscribers will, according to the devs, always get more cash shop "points" with their monthly renewal than the mission packs will cost...it's free content for subscribers, although it will leave you with less to spend on cosmetic items and such that month. Not every month will get a cash shop mission pack (they're devoting the majority of content development resources to "regular" content everyone will get.
So far, it looks like Funcom are handling B2P very well with this game.