Is Star Trek Online worth it?
If you're a fan of Star Trek, the answer is yes. It's worth playing through all the story missions.
Is it another Pay To Win game?
Short answer: Mostly no.
Long answer: There are two phases in the game, the leveling up phase and the end-game phase.
The leveling up phase consist of playing the main story-arc missions, which should get you to level 50+ in about 1 week to a month (depending on how much you play everyday). You are given a free ship at levels 10, 20, 30 and 40. If you are a subscriber, you also get another free ship at level 50. So during this phase, you don't have to pay anything and there are lots of players who do this to enjoy STO's story.
When you hit level 60, which is STO's end-game levels , you may want to invest in a better ship if you decide to stick with the game for the long term. An end-game ship costs either $25 or $30, but certain ships can be further upgraded with either a Ship Upgrade Token or a Fleet Ship Module (both costs another $5 ). Theoretically you are set after that and don't need to spend anymore money. Also note that playing end-game stuff earns you dilithium, which can be converted into PWE's Zen currency. So if you play a lot and collect a lot of dilithium, it is possible to buy ships without spending a single dollar.
If you're like me and just love collecting beautiful looking or powerful ships, then yeah that's when the game can become potentially expensive. In the first year, I splurged on a lifetime subscription ($100+) but in return I get a monthly stipend of 500 Zen which allows me to buy a ship for free every half a year.
What makes it a good MMO?
Starship based MMOs are very rare. There are only two main choices, Eve Online or Star Trek Online. I picked STO over Eve because Eve requires a huge investment in money and time.
What makes it unique? Why do you play it above other MMOs?
STO is like Lord Of The Rings Online where there's a continuing storyline. At times, the story can be quite epic in scope dealing with a galaxy-wide war and now a temporal war.
STO is not a traditional MMO like World of Warcraft that targets hardcore players who play everyday and strive to be the best of the best. STO is aimed at trek fans who may have never played any MMOs. As a result, STO is very casual-oriented MMO. You do not have to play everyday. The main storyline is almost like a single-player campaign, its possible to group up for missions but most players don't. You don't even have to optimize your character much. There are no hour-long end-game raids. Instead, STO's endgame consists of 20-30 minute "queued events" runs with a random group of 5 players.