I have a decent amount of modern figs in my pool to play around with for Brotherhood/X-Men options as far as turning them into Marauders. Here are 3 teams I was thinking without putting much thought into it yet:

Team A:
265 Mr Sinister + full gauntlet
100 Dark Phoenix
75 Scarlet Witch
59 Storm M10
=499

That gives me 2 perplexes with Sinister/Witch, 3 solid attackers, an outwit, & a probs control. My mobility is decent with double TK, & Storm/Sinister can go in stealth.

Team B:
265 Mr Sinister + full gauntlet
123 Professor X
75 Scarlet Witch
35 Roulette
=498

Drops the third attacker in Storm for an extra probs so I'm more likely to land with those 10ATV & switches Phoenix for Xavier who can shoot through a stealthed Sinister. I do lose potentially 2 attacks every few turns with the loss of Power Cosmic and a 3rd attacker.

Team C:
225 Mr Sinister
123 Professor X
100 Dark Phoenix
50 Scarlet Witch
=498

Dual outwit, dual perplex, & a prob control. Loses the gauntlet & 2 clix off the witch, but it gives me three excellent attack pieces with no real holes. The main concern is how Sinister plays with no willpower & being outwit-able.

Anyone else have any ideas? I'm sure these teams have flaws, but I've yet to use Sinister in tournament play and he looks fun.

Theres a different thread with 600 pts instead of 500 on the theme teams section of the forums, you can look there too. However, I'll give you my opinion here anyways.

Between your two teams, I prefer the first one, here's why:

Team 1: I am not a fan of the gauntlet, but w/e. This team is pretty well rounded and doesn't have a problem with movement due to telekinesis. The sinister/d.phoenix combo is great too. It's just a very solid team.

Team 2:Again not a fan of the gauntlet, nor of Prof X(he's cheap takes the fun out of games, and yea I like having fun even when being competitive.) However, this isn't an argument about having fun, but rather how well the team will do. Again, its a solid team. However, I feel that if they take out even one of your characters, you will be in big trouble. Even more so if its Sinister or X, unlike the first one where you still have a really good chance despite who goes down.

Here's my 500 point team for Sinister:

CW047 Mr. Sinister 225
FFCW006 Scarlet Witch 75
M10A021R Dark Phoenix 100
GX049 Archangel 99

X2 perplex, x1 prob, x1 outwits. Lots of mobility and good attack/defense values everywhere. Not to mention archangel has move and attack, which is great against those stealth opponents. Having the perplex and prob will help guarantee he hits. This is a team where all the pieces are deadly, and it doesn't depend on just one figure.

Yeah I like the Archangel, I just don't own one. I've been trying to trade for him, but no one seems to want to come off him. I'm also leaning on the first team, but feel like there is probably better options.

Added a 3rd team which gives me the best lineup of figures, but loses the flexibility of the gauntlet, and is probably a bit less mobile than the first team with the loss of willpower on Sinister & TK on Witch... Sinister/Prof X/Phoenix do seem like a very nasty trio of attackers though.

You still have Tk with Dark Phoenix too. Also, I believe stealth characters can not be outwitted even when the one using outwit is adjacent to him.

Why? Well Outwit requires LoF, and stealth blocks LoF. I believe this would be the same on perplex when it isn't your turn(unless things have changed, which I doubt)

I actually like this team the best with Team A a close second.

I agree with LittleWing. Team C is the best from unoutwitable stealth while you have just awesomeness of prof and a pulse waving phoenix. Hope i helped!