Honestly, I'd pass at this point. When there was a monthly fee, it made a ton of sense, and even early in the F2P era, you could rationalize that you get a bunch of stuff, and it's still a young game, etc.
Not that it's dying, but game has been around a while. How much would you pay in Zen and a month or two of subbing vice what the LTS costs? How long do you have to keep playing to make it a break even scenario?
If there's a big LTS sale, maybe
, but not sure it's worth it anymore...