You'll have to ask yourself what the point of you playing the game is. Is it to get your character to lv50 and then go through all of the endgame content, several flashpoints a week, raids/operations, lots of pvp/warzones? If it's any of those things, then subscribing is for you because, while they're available to F2P folks, they're limited.
Doing anything else in the game? Don't really care if you miss out on some cosmetic things and some small things that make things a little more convenient? Then F2P is the way to go... and if there are specific things that you'd like to take advantage of, become a Preferred Player by buying something worth at least 5USD from the swtor store. Other things can be bought using cartel coins if you choose. Still cheaper than subscribing.
There's absolutely nothing wrong with F2P, it's a really good system that lets you play the game without any real restrictions, just a little bit of inconvenience when compared to what subscribers get.