It took Marvel long enough to release higher-res images of these posters, but it's taken even longer for me to get these posts out, so I guess I can't complain. Let's look at what's supposed to pass for Hawkeye in these movies:
As usual, we've got an unnecessarily cluttered outfit (the head of Marvel's costume department must be a huge fan of '90s superhero comics). Would it really be so bad if he wore something that actually looked like a vest that someone might wear in real life? You can see a half-hearted attempt to incorporate the purple from the comics without alienating non-comics readers that think purple is 'gay.'
I swear, he's not gay.
The pose here strikes me as particularly lazy. I'm not sure why they decided these posters should be action scenes without any action. It's not like anyone would want a poster of a superhero fighting something. It would have been so easy to find an effective action pose for any of these characters, but especially so when you have a prop like a bow to play with. It's true that Jeremy Renner's acting ability only goes so far, but I'm sure they could have done better than a bored, slightly confused look offscreen, like he's trying to solve a simple algebra equation.
At least Captain America is showing even the slighted amount of emotion in these posters. You even get a sense of his uprightness and determination in this one. It's not enough to make a good poster, but at this point I have to take what I can get.
On the other hand, we get a better look at whatever the hell is happening on his costume, and it's not good. Cap's comic costume is an uncomplicated design that works both conceptually and visually.
Next up is the Scarlet Witch, doin' one of her spells:
The first thing I notice here is the lack of attacking robots. Instead, we've just got two standing on the building in the back looking around in confusion. They must have been recharging their batteries when everyone else went off to the fighting.
But back to Scarlett. Er, Wanda. Well, she's standing there, which honestly is more of a decent pose than any of these others. She's using her power, doing the Marvel magic finger thing. She's kind of wearing red, I guess. And they got the whole 'gypsy' thing across, thankfully without some of those giant hoop earrings that I'm tempted to rip out of girls' ears whenever I see them (seriously, don't wear those, they do not look good). I wonder what they're going to do about her when she shows up again after this. Is she always going to wear the same clothes? The comics' Scarlet Witch has a great costume, but I don't see it making sense in these movies.
I've been waiting for a goofy Quicksilver poster, and yeah, it's goofy, but I still can't help being disappointed. It's just another boring image with the truncated figure taking up most of the frame. Pietro looks like a huge douche, which is accurate to the comics I guess. His outfit was never that great in the comics, but this looks like some kind of Under Armour shirt that would end up sitting on the rack because nobody would want a shirt with such crappy visual design. I don't like how they've portrayed his speed so far in the trailers, and this poster doesn't change that. Quicksilver isn't the Flash, his speed is usually less exaggerated, but I doubt the movie will match that. On the plus side (if there is one), this is the only poster that features at least some sense of action, with Pietro running away from the robots flying after him. Still crappy.
Our final poster is of our Big Bad, Ultron himself:
Is it another crappy poster? Kind of, yeah, but at least we can see what we're looking at better than we can on any of the others. Forbush forbid that we see his entire body in the frame though. As for his design, he basically looks like the comics' Ultron, except for being made out of CGI instead of adamantium. However, the movies again opted for excessive and unnecessary clutter all over. While his comics body did tend to be a little generic, his head/face design is iconic for a reason:
Because it's awesome.
Is the new head/face better than the old? Well, it gets you facial emotiveness I guess. But personally, I think it's a big step down. It reminds me of the way these movies always have the hero take his mask/helmet off so you can see their face, even if it makes no sense in context. Hell, these posters keep doing the same thing with Iron Man. I this case, I think it could have been really interesting to have a villain who's face was just a blank, emotionless mockery of a human face. Anyone talking to him would have no idea of what he was thinking or what his reaction to things was. If someone was trying to talk him out of his plans, they (and the audience) would be left wondering if their words were getting through, at least until Ultron responded (probably with an energy blast).
Either way, I don't find the movie's Ultron design interesting in the slightest, but at this point I shouldn't be surprised.
I'll let you play The Matching Game on your own. At this point I feel like I know all those duplicating little background robots on a personal level.