Players who still pay for their subscription (now called Patrons) get convenience items (ex. faster mount speed) and boosts (xp, tokens, favor, currency) automatically. There is also an in-game store for micro-transactions of the same type, plus things like more bag slots and vanity items.
So it's definitely NOT pay-to-win here. Spending money on the game will speed up your gains, but an FTP player will catch up to them and be on a level playing field, just with more time spent leveling. Inevitably, there will be cries of "pay-to-win!" but with buyable items being convenience and boosts, while not affecting a character's stats, I'm not seeing a good argument for that take on it.
I'm a big fan of this model. It worked for Star Trek Online, converting largely empty space in-game into thriving zones of players. Many were free to play but still spent money here and there, those with subscriptions enjoyed the benefits that it gave, and everyone got to play the same content unrestricted. Hopefully, we'll see the same effect for Rift, turning the game into a better revenue-earner for Trion. I'm curious to see whether or not they'll end up offering a Lifetime Patron subscription.
Compare this to Star Wars: The Old Republic's "free-to-play" model where nearly everything worth doing is restricted unless you're willing to pay for it on a regular basis, and you'll see what a great idea the Rift/STO model is and all of the positive things they give to their FTP gamers.
Definitely give Rift a try - you have nothing to lose and you may just have a fun and rewarding experience.