What should I be aware of going into PvP?

[Februs]

I actually had a fun time with FFXIV's. Perhaps it's the lack of toxicity, as I haven't seen anything harmful yet

... Wut?

I am sorely tempted to sign this or save it somewhere so I can whip it out next time some salty PvE'er complains about toxicity in PvP lol.

Jokes aside, there is some salt in the PvP community. You'll find most of it in Feast, because the game mode is ranked and each loss counts big time against your standing. The matchmaking is also a rotting cesspool of shattered hopes and dreams, so people can get pretty upset pretty quickly. Brace yourself, and try not to take it personally. Learn. Grow. Keep a tough skin, and don't feed the trolls. That last part is especially important, because in a game like this, anyone who is spending more time chatting than fighting is probably doing much worse than the people they are complaining about.

As for your question, I'll just get to what you specifically asked about.

• 1. GEAR
  
  The short and simple answer is that any PvE gear at ~190 or above will be fine for PvP, and you won't notice any substantial stat gaps. The slightly longer and more complicated explanation is that, if you're interested in optimizing your PvP performance, than you have to look at minimizing and maximizing your stats. That can only be done by creating a custom build with a healthy mix of PvP/PvE gear.
  
  The first thing you have to realize is that all stats are NOT equal in PvP. There are some stats that you simply don't use. The accuracy requirement, for example, is quite low in PvP, so you DO NOT need to cap that stat to never miss a target. Slotting additional points into that stat beyond the minimum requirement is pointless and wastes stat allocation. The second thing to realize is that all stats are synced down to lvl 150, meaning that your stats are capped at that level. Say, for example, that the stat cap for Det is 100 (it's not, I'm just throwing out a number). Even if you stat 500 Det, you still get synced down to 100, so slotting that additional Det does nothing except waste gear space.
  
  The idea behind min/maxing your secondary stats is to find the right mix and match of gear so that you can cap the stats you actually need, whereas you leave the stats you don't need below cap or at their minimum requirement. It is important to note that those stat caps are different for each job, and each job also prioritizes different stats. You also cannot preview the stat caps until you are actually synced within a duty, so it'll take some tinkering back and forth before you get your build right. You should also keep in mind that we are talking about peanuts between a purely optimized build and one that is simply running with your run of the mill set, so I wouldn't take it too seriously if someone gripes at you for not running a pure meta try-hard build. Some things (such as Crowd Control) are not even effected by optimzed gear, so there is a certain level of stat discrepancy that can be bridged by simply playing better than your opponent.
  
  
• 2. HEALERS
  
  Are abused in PvP.
  
  I'm not going to sugar coat that for you. They are one of the hardest jobs to play in PvP, they are utterly essential, and they are just as underappreciated. Healers are often the fist priority target of the enemy team, because a good healer can make or break a match. They are also the first person yelled at when things go south. That said, there is a reason for that. Most PvP'ers have seen good and bad healing, and they can spot the difference between a PvP vet and a PvE guppy right off the bat. I can not stress this enough, if you chose to heal in PvP then you best bring your big boy pants, expect a steep learning curve over PvE healing, and grow some very thick skin. You also need to learn how to protect yourself, because there's only so much your team can do for you. There's a limit to how much CC your team can provide, and baby sitting a weak healer can cost the match. It's better if you learn to take care of yourself, because you won't be able to rely on your team to do it for you all the time.
  
  
• 3. NEWCOMERS IN FEAST
  
  Oooooh this is a controversial one. Quite frankly, I don't think there's a PvP'er in the game who does not want new people to join Feast, because we all want to see the community grow ... That said, Feast is ranked. Getting new players consecutively can cost you your standing. New healers, in particular, are the bane of ranking up, because they almost always lose their matches, especially against higher ranked healers. For that reason, new players are often discouraged, or outright hated, when they join Feast. That's also partly SE's fault, because the matchmaking is absolutely awful and pairs high rankers with low rankers, even when it shouldn't.
  
  That said, I wouldn't let that discourage you. Join up. We need more players, and you're only going to get better in Feast by playing Feast. Also, you pay your sub just like everyone else, so the game is there for you to try out. Give it a go and to hell with any haters you get. Just makes sure that you actually try to learn from your mistakes and try to improve. Most PvP'ers are more than happy to help a new person if they actually show sign of improving. If you keep making the same mistakes over and over, however, then they are far less tolerant of seeing you in consecutive matches.
  
  
• 4. PRIORITY HEALING
  
  You don't, technically, "stick" to anyone in PvP as a healer. You just maintain lines of sight. In Frontlines this is a little trickier, because you have a HUGE team and they can all scatter to the winds. In that situation, you just have to make a tactical call. Go where you are needed. Just remember that "where you are needed" is not always where your team is dying. When all is said and done, all PvP (including Frontlines) is objective based. There is no point to you putting your neck out to rescue a bunch of players who are making their last heroic stand in the middle of nowhere for the sake of nothing, especially when you have another set of heroes out there doing the exact same thing ... only they're fighting for an objective.
  
  The rule of thumb here is to weigh your priorities and the priorities of the team. How many points do you stand to lose? How many do you stand to gain? It all changes on a case by case basis, so you have to make the best judgement call you can in the moment.
  
  As for Feast, that changes a bit. In Feast, you don't have to decide which group to follow. You only have one group. What you have to do instead is decide who gets priority healing within that group. That can be decided based on ticket count (who has how many stacks of medals), enemy burst rotations, and your own mana reserve. Most of the time, you're going to want to stay out of the way to discourage people from targeting you, and when they do target you, you'll have to kite them around the map to avoid dying. While you do that, your 1st priority is to keep lines of sight on your teammates so you can actually heal them. If they break LoS, give them a shout to stop being a moron in the chat box. After that, it's just a matter of making a judgement call on who needs to be focused.

That came out much longer than I intended, but I hope it all helps. I'll shrink it down in hidden bars to keep it nice and compact for you. If you have any more specific questions, ask away. Most of the forum people are actually pretty helpful with this kind of thing.