National Assoc. For The Advancement Of Young Entrepreneurs
I just purchased a founders pack and I plan on making my character right after my classes today are over. I'm still kinda new when it comes to mmos as I've only reached max in Tera. I played a lot of Tera and mainly focused on PvP. In Tera there is most definitely a tier list on what classes are good and which are Blade And Soul Items. Is there a tier system in BnS as there is in Tera? Another thing is that in Tera I was a gunner/Slater main. What classes are similar to those in BnS?
You make it sound like you expect to have access to the servers today. This is wrong since the next beta will start on the 24th and only then you will be able to create a character.
You can however download the TW client and create your character there if you want to do it today (you can save the preset and use it in the western server).
Other than that, the classes aren't really comparable to Tera. I guess the Warlock would kinda fit the playstyle because it's a more stationary burst class than the others. But in my opinion, you should just pick whatever class looks cool to you.
Echoing what others have said and adding to it: it's a bad idea to decide on a class based on the current "tiers", as once 50 hits (which can't be toooo far behind), every class becomes pretty balanced, with warlock having a general edge. I think BnS is very much so find a class you play well and mesh with and that will undoubtedly be the best class for you; there's no class where a player can play mediocre and succeed against anyone with marginally more ability.
As for comparing against TERA: you really can't. I put a lot of time into TERA when it was released, as well as a year following, and I have yet to find a class that feels like it plays similarly at all, especially to get more BNS Gold. I'd just give up on looking for similarities and instead focus on what archetype you enjoy and go from there. It's also worth downloading the TW BnS and then taking each class you have any interest in playing to at least 10 to get a very basic and general feeling.