I would encourage you to play a few games of each and get a feel for them. I love them both and play them both. I will say that it is easier to find xwing players than armada players, though where I live, both are scarce.
either can represent a substantial investment. play them both a few times and see what you think. If, like me, you have to grow your own players by introducing them to the game, then x-wing is far easier to learn the base mechanics of the game. that isn't to say its better, but it is easier to teach and less intimidating to people who are trying to pick it up.
in my experience, xwing is not cheaper, they are both expensive, but I tend to be a collector, and I have 3 to 4 or more of all the small base ships and 2 of all the large base, so..... that's a lot of cash, but it's spread out more than my armada spending.
But if I would say one thing, it would be play both at least a couple of times, then buy the one you like the best.