Here's a pretty decent checklist to decide if MES are your kind of eye shadow or not:
Q: Do you like to apply and wear shadows that go on very pigmented and then get blended out OR do you prefer shadows that you need to apply in layers and build up the color? I like applying it layer by layer, I don't like I am the best blender so I adding layers actually helps me get to the best look much better.
MES look much better when you do a thin layer and then another layer or so on top. Also, I find that most MES don't blend well into each other or into other shadows for that perfect, watercolor effect - lots of blending down can make them look muddy (they've gotten much better in this department, though). You have to layer them into other shadows for the best look or go for simple washes of color.
Q: Do you like shadows that are shimmery, but not wet look? Ok so I am so too much into the shimmery, I don't like a crazy amount of it but if the MES are like the blushes and SF then it shouldn't be too much of a problem since I fell that these don't have a crazy amount.
MES are very shimmery, frosty and glittery usually, but have an underlying dry look. If you wet them, they get frostier but also heavier looking. If you apply them dry, you can get a semi-sheer veil of color with more toned down shimmer. In HC, only a few are more on the matte side, but normally you don't get sheen, like you would from a moister product. They don't accentuate eyelid texture unless you apply them too heavily, and then all bets are off.
Q: Do you like really complex colors that shift in the light and colors where you can get different shades from one pan? Ok so I rather have one single color because I feel that it could be easier for me to deal with specially since I often like to wear my makeup to the hospital I know that I can't have something on that its too much. And then again these might just be for special outings unlike the blushes.
You'll be in heaven with MES if this is what you like. You will always get a subtle, sophisticated color effect, rather than super bright and punchy. Even the brighter colors have a way of blending with your skin tone and reflecting it, rather than just laying on top, covering everything else that's there.
Q: Do you need super-long wear, without fading? Long wearing is definitely a plus, or I like it to stay put when I go out on date night if it can go for a good 5 hours I'm good if not then I tent to pass on it.
MES don't wear as long as standard powder shadows often do, but they've gotten much better and the HC ones are the best wearing I've seen - you can get through the day without most colors fading. If you have wear issues, you need to prep your eyes better - especially make sure to have plenty of moisturizer if you have dry lids. A lot of wear problems come from applying them wet with too wet a brush - I prefer to apply them dry and then do a wet layer on top, or apply dry and then spray after application with Fix+.
Q: Do you have sensitive eyes? Not normally so this is not a concern for me.
Some people can get eye sensitivity with MES - I used to but I've found I have much fewer problems with the newer ones and also do a lot better with them when I don't use a wet brush to pick up product - the MES that I've never gotten wet haven't irritated my eyes, while the ones I used wet brushes on are hit or miss. Ones with a lot of glitter are better to keep away from the tear ducts.
Those are the main issues pro or con that I've found with MES. Personally I love them and wear them more than standard powder shadows, but I can see why some people prefer standard powder shadows.