The draw backs are not so bad... until you sub a short time and get use to the advantages of paying like i did lol. Now as a non sub I notice them more. Still I did just fine without subing. some unlocks are helpful, and simply buying anything worth 5 bucks gives you a nice boost as a Preferred status player. You do not need artifact gear, it's not that big of an advantage at level 1-64. You will max out at level 50 and the main story line. You will have to pay for the 3 expansions level 51-65. But if you sub for even one month your get all 3 expansions and Preferred status. So something as Simple as 15 bucks can get you all the expansions and some boosts. Note though Try to be a sub at level 65 as the armor mods (things added to armors to make them better) are Artifact sadly, and are unlike before worth having. Once you have an artifact items, it stays usable by you even when your sub wears off.
Galactic trade market is your best friend for items, just like BG's auction is.
I'm not sure what it adds up to but two unlocks are handy to buy if you wish: 
Color matching (sinks all the colors to your chest armor, rather then needing to buy a dye for each part), and 
Hide head slot (hides your head armor as it can be hard for some to find something that does not look stupid on your head, though some classes find decent head gear easier to find). I went a long time with nether though lol. 
In short being a Sub like Ragingpeace said is a major boost, the game is still fun...and free 
