Okay, for starters, this information is most relevant to those who PVP or share my style of play, so your mileage on my advice may vary greatly. Every time a new character or costume is released, alot of dust gets kicked up on this site over how best to spend Command Points. Should I get this character or that character? Should I get this costume or that costume? And finally, should I spend the extra CP on a particular alternate class?
I thought the best way to breakdown these choices is weighing the pros and cons of each class, so here's the countdown, starting with my least favorite:
I want to make it perfectly clear: there isn't a single character in this game that can't be used to win a match. All the players complaining about Hawkeye, or Nightcrawler, just aren't using the characters properly. I don't call Blasters the worst class because it contains the worst characters. Far from it! Their hero bonus improves attack, so if offense if your thing, stock up on them. Scarlet Witch is (and Cable will be) an offensive powerhouse when ISO'ed correctly, and have great defensive options, healing or buffing. They can make short work of tough Bruisers, and keep the real heavy-hitters from hitting their strides...
...but they have a serious downside. Most of my play-style centers on making sure I have the best team defensively while probing the opposition for weakness. And a Blaster on the other team always makes my job easier. Why? The strength of the Tactician Class. If I can land a single-target attack on an enemy Blaster, I can either use the second attack to go ahead and take them out of play, or, if they don't have an Infiltrator as back-up, I can switch gears, to an AOE-attack that leaves them alive to take advantage of next round, to heal up my weak party members, or to recharge for a much larger assault. In a turn-based game, extra turns kill. So while Blasters can hide behind a tough wall for protection, psychic attacks from Emma or AvX-powered Tactician Agents leave them no quarter, and turn their hard-hitting strength into a liability for their entire team.
Advice: Don't avoid purchasing Blasters, I can't recommend them enough! But since I'm listing this as my least-favorite class, all the characters you can convert out of it, you should. Cable and Scarlet Witch are here since they are the only Blasters without alternates. Very soon, Cable will be all by his lonesome.
This class gets my vote for most variability. So again, I'm not calling these characters bad. I can't say enough that my game is all about defense and some of the characters in this class really bring some serious stats when it comes to absorbing damage, and GR's passive makes the opposition defense weaker the longer he stays in the fight. Their hero bonus goes to your accuracy, which is a must if you plan on landing those deadly criticals. But with guaranteed hits comes their greatest downfall...
... Enraged. I'm currently rocking a Bruiser Agent, For my money, it's the best trade-off for hard hits, taking and giving. I've got all my Agent's slots packed with Strong-Iso's, and running into a Scrapper makes him hit that much harder. After duking it out with Iron Fist, I can get my agent doing Hilk-size damage with stacked Enraged, and that makes this class vulnerable. Their class bonus can even be turned to your advantage, if you have any Infiltrator-Bruiser combination on your team. Hit with the Infiltrator, giving them CQC, the wall with a Bruiser. You'll get your stacked-Enraged that much faster.
And remember when I said greatest downfall? It's because they have more than one: the same thing that makes Tacticians so great is what makes Scrappers so faulty. Unlike a Tactician, who can move from one target to another, or use the extra turn to heal, the Scrappers are left an extra attack on the same target. Most Scrappers are not serviced by this, and the ones with better follow-up attacks can be placed in better classes.
Advice: Daredevil and Iron Fist have new costumes coming down the pipe soon, and based on their current costumes, I think it's a safe bet that Magik and Quicksilver will soon follow. The only character I would consider leaving in the class would be Sif, and even then, her alternate costume would be better served by stacked Enraged, as opposed to Close Quarters. Basically, no character does, as a Scrapper, what Mockingbird doesn't already do better.
I love Bruisers. Did I mention I LOVE defensive play? Well, guess what ther hero bonus for Bruisers adds up to? When you absolutely must decimate the other team, they get the job done with none too much fuss. For a short period of time, Bruisers Spider-Man and WW2 Cap owned the meta of this game, and even though PVP is full of witches lately, running into a team with two Bruisers is possible, and whatever is hiding behind them is sure to be well-protected and worthy of your efforts to kill first and foremost. Why not just kill the Bruisers first to get to the Witch, Agent, or Psychic inside? Well...
... staying power. Most Bruisers are big, making them easy targets. Cap's passive and Spidey's high Evade stat remain the sole exception to this rule, though the P5 Colossus uniform adds some health regen to keep him up and at 'em. All the other Bruisers aren't going to be dodging much, witch wouldn't be so bad if not for some of the hard-hitting blasters, especially Scarlet Witch. Without someone to buff or heal them, Bruisers, despite all their offensive power, can be debuffed and outlasted. A knowledgeable player will try and get behind their defenses, demolish the healer, and then pick the titans apart. Leaving what the Bruiser is protecting alone to will only leave you a with a healing, buffed, possibly Enraged Bruiser. This is exactly what I'm counting on when I'm playing.
Advice: Before the Future Foundation outfits, my advice would have been very different. But with the buffs added to Thing, there are really no bad choices when it comes to this class. Except for vanilla Thing, obviously. That being said, not all other choices are equally good: Human Torch packs serious heat offensively, and is immune to burning attacks, neuturing characters like Phoenix, She-Hulk has the ability to roll out the Enraged full-strength in one turn, and World War Hulk remains the best offensive tank in the game. Colossus should get an honorable mention, as he is great at absorbing damage, physical and psychic. But it should be noted that Bruisers are NOT the best walls in the game. So if your game is defense, stay tuned...
Oh, and a special note with regard to the topic at hand, which costume should I choose? The pictures in these galleries give you my choices, but whereas the two previous classes are full of characters that don't have viable alternates just yet, I'll justify myself when it comes to these picks. Thing and Colossus are fairly obvious. Future Foundation Thing is just plain better, while Modern Colossus beats out the standard Ruskie and his P5 suit, as, for me, he's really only about Steel Curtain. Thor and Hulk are a little more nuanced: I grabbed Avenger Thor, but not Avenger Hulk. Why?
Both Thor and Hulk have to build, so whatever makes them build faster makes them better. For Thor, his Avenger suit helps him get two stacks of MoM fast, whereas his vanilla doesn't help in this regard, and while his Modern suit gives you the two MoM's right off the bat, they don't hit as hard with Empowering Strike to beef them up. Thor just plays better as an Avenger, and if you have another on your team (or Coulson's Revenge), he'll power-up faster and hit harder.
WWHulk get's my pick for best Bruiser, but I understand why some might prefer his Scrapper suit. Either way, I'm expecting Grey Hulk is going to alter the debate, so I won't write too much in his defense for now.