Gwiniel covered everything very good I think. This is, simply put, the pros and cons about the servers, in my opinion anyway:
New Frontier
Pros:
+ You can play for free if you want.
+ Has the highest population of all the servers (although it's still not very high).
+ Has an Exchange NPC, so you can convert in-game gold to Cash Shop currency.
+ Easier to find groups for Astral and Raids, and skirmishes (PvP) happens more often because of the higher population.
Cons:
- In order to enjoy end-game content, especially PvP, you will require a certain amount of items from the Cash Shop, because players who own these items will have a significant advantage over players who don't.
- The exchange rate for exchanging in-game gold for Cash Shop currency is ridiculously high, so it would take years to get enough gold for all the items you will need, if you want to play for free. We're talking years of gold farming, a lot of patience and commitment.
- Old players will already have a big advantage over new players, so if you're not spending a lot of real money for the necessary Cash Shop items right away, you will have to endure a long time of being totally crushed in PvP and out-damaged/underdeveloped in PvE.
- Slow road to max level. There's no default exp boost apart from certain exp boost events every once in a while.
Equilibrium
Pros:
+ New server, meaning everyone starts on the same level of development and it will be easier for new players to catch up.
+ New blood = fresh start with new community and a change of atmosphere. Change is good
+ Might bring old players back who are curious to try something new.
+ Free items for leveling up. However most, if not all of them are temporary, but you get fragments from them which adds up to eventually give you the item permanently.
+ Exp rate is permanently increased so leveling is less slow and tedious.
Cons:
- Low population, and it might not get much better because advertising is a weak point on my.com's (publisher) side.
- No information about future plans etc. has been released for the server, so we don't know what the plans are and if it will be any different from the New Frontier server.
- No Exchange NPC. This means the server can safely be defined as even more 'Pay-to-Win' than New Frontier, as the only way to get the necessary Cash Shop items is to buy it for real money.
- No major changes from New Frontier so far, which means it will probably not be very successful.
Smugglers Paradise
Pros:
+ Subscription model. This is the preferred game plan by most people in the MMORPG genre I believe, as it tends to be the least 'Pay-to-Win' and the most balanced option. This is most likely why the most successful games are the ones that have either a subscription model or a "buy once, play for free"-type of game plan.
+ Balanced. Here it's all about the gear and acquired items from Astral and Raids, as well as the skill of the player.
+ Nice and friendly community. They are always proving to be really dedicated to keeping the server alive and helping new players progress.
+ Increased exp rate permanently.
Cons
- Extremely low population. As a result of this, things like skirmishes (PvP) and dominion rarely happens, and a lot of planning is required for different activities.
- Seldom any trial periods for new players to be able to try it out for a week or so, and poor/no advertising, which means population will not grow.
- You will not get the full experience and see the full potential of the game, because of the low population.
Conclusion:
New Frontier - If time and money is an issue, don't play on this server.
Equilibrium - If money is an issue, don't play on this server.
Smuggler's Paradise - If low population is an issue, don't play on this server.
If time, money and low population is all an issue, don't play this game.