Newbie kinda lost about food...

I have 3 cats which I have had for a couple of years. I used to feed them Iams ProActive Indoor weight and hairball control. After reading on this site and hearing from others that the first ingrediant listed should be a "meat" not just a "meat meal" I switched to Purina One Natural Blends. Since then the amount of cat vomit and hairballs has increased greatly. Having said all of this and from what I have read here I may try the Nutro line of food. However, through reading I have become confused over brands, wet versus dry, corn, etc...

My cats are a male about 7 years old, another male going on 5 and a female who is probably around 9 or 10. None of them have any medical requirements so I guess I am hoping for a little insight. Any suggestions? Is the Purina One Natural Blend not a good food? Thoughts?

Actually that's backwards.
Chicken meal is more meat by volume than just chicken.
Meal is simply the meat with the moisture removed.

Nutro is a good brand in about the same price range as Purina, and usually has corn gluten meal (a protein source) but not whole ground corn, which you want to avoid.
Just check the dates to avoid the recalled batch.

Wet is better than dry, your cats will have better dental health, less likely to become obese, lower volume of stool, and will be taking in more moisture (cats are not prone to drinking enough).

Dry is fine though, but if you can add wet to their diet as well, even better.
I free feed dry (thankfully my girls are not prone to overeating) and they all split a 5.5 oz can of food every evening.

The simplest thing is to get something that fits your budget and lifestyle, and that your cats will eat and thrive on.

The best, most expensive food there is is worthless if they won't touch it, or don't thrive on it.