For various reasons, we're going to cover all of the current Chex cereals in one post.  We will also be leaving out the 6,000 varieties of Chex Mix. 
If you somehow don't know what I'm talking about when I say Chex then you should really get out of your bed more often and/or watch something on TV that has commercials. 
Visually all of the Chex are the same: little crispy squares of interlaced grains, vaguely pillow shaped  so they can hold milk.
With one exception they all have the quick to soggy problem of many grain cereals. They aren't as bad as corn flakes, but you'd still better not dally once the milk hits the bowl.
Corn/Rice Chex: I realize that these are two different varieties of Chex and thus might deserve two different grades, but let's be honest, besides the name and a slight color variation these two are interchangeable and otherwise identical. They don't taste bad, but then again they don't really taste like much of anything. They are also the quickest to turn to mush in your bowl.
They also come in a box larger than your average cereal box. This might seem like a boon, but after you've eaten five bowls and are now sick of them, the box will sit and mock you from the pantry shelf for the next six months until you finally overcome the potential guilt and just throw them away.
Corn/Rice Chex: B- 
Wheat Chex: Wheat Chex is the exception to the "Chex gets soggy quick in milk" rule. They will eventually lose a bit of their rough edges, but unless you go off and watch a Peter Jackson movie between pouring the milk and eating, they will maintain crispiness throughout.
They taste pretty good. Their taste improves significantly if you sprinkle just a bit of sugar on them.  I honestly buy them pretty regularly.
Speaking of regular, you want to be careful about how much Wheat Chex you eat. Alternately, if you decide to finish off the box in a few consecutive sittings, I would suggest not straying too far from your favorite toilet. Too much Wheat Chex will clean you out like a freight train through your bowels. 
Wheat Chex: B
Honey Nut Chex: This is the dirty trick of Chex varieties. They promise to be so much more, but then fail to deliver. 
Honey Nut Chex [calling from cereal aisle shelf]: Mr. Customer! Buy me! I am sweet and delicious. I have nuts. I have honey. I am so different from these other plain varieties. You must buy me!
Me: Um. Isn't that what you said last time?
HNC: No, that wasn't me. That was Crispix.
Me: Are you sure.
HNC: I promise. Think of the honey. Think of the nuts. Think of the children.
The next morning you discover once again that you've been fooled into buying a box of Corn Chex in which the cereal has a light coating of something that makes it glisten slightly before it gets wet. Once the milk hits them the truth is revealed and both the you and the Chex are sad.
Honey Nut Chex: C-
Vanilla Chex: A relative newcomer to the Chex Universe, Vanilla Chex rode in on the heels of Chocolate Chex [see below] and made it's bid for glory. Alas it bid too low. They are not bad, but not good enough to ever bother buying unless the store is out of Chocolate Chex.
Vanilla Chex: C+
Chocolate Chex: They is where the goodness lies. Chocolate Chex are good stuff. Chex covered in cocoa powder and other chocolate-y type goodness. But they don't coat every piece. No they leave about a third uncovered and normal. That way you can still feel like you are eating a "good for you" cereal.
They are good with milk and they are good by the handful straight out of the box. In fact, I usually end up eating them both ways since once you're done with a bowl of them, you wanna have more. 
Chocolate Chex: A
Cinnamon Chex: I must admit to having failed you in my quest to fully educate you about Chex. I actually have never tried these. I think cinnamon flavored things are okay, but the flavor doesn't really excite me terribly. Thus, I have never bothered to buy these, though there were two or three times when I thought more than ten seconds about it, but then I bought Chocolate Chex. 
Chex on Amazon
Cinnamon Chex: ??
Chex Clusters - Fruit and Oat: While thinking about writing this post, I discovered online that they now also have a new variety of Chex. Once I see them on a shelf, I'll buy some and update this post.
Chex Clusters: ??
Past Varieties: Doing some research on the Interwebs  I found out that there are several past varieties of Chex that have come and gone. Most of them I had never heard of,  but I do remember Frosted Chex. Not well enough to grade them, but enough to visualize the box in my head.
I have clear memories of Bran Chex. If Wheat Chex is a freight train, then Bran Chex was Grand Central Station with all lines running.  Also it tasted worse than Wheat Chex, so I'm not surprised it went away.
Finally, I have a memory of a Chex cereal that had little bits of nuts, brown sugar or other crunchy type goodness hanging off of each piece of cereal. I don't recognize any of the list of Ex-Chex types as what I am remembering, maybe it was the Honey Graham Chex. I just remember liking it. 
Chex Cereals: B+
 - Not the least of which is that I'm lazy. Also, other reasons that should be evident as you read. Also, if you haven't already read it, here's a really old post about Cereal in general you can read.
 - I'm also not commenting on the Gluten Free Chex Oatmeal, because Oatmeal is nasty.
 - And not just the same two commercials you get on Hulu during any given stretch of time
 - Couch not bed.
 - They probably scored a little higher than you might have thought given the commentary, but they are redeemed in part because of Muddy Buddies
 - That wasn't a joke saying you should pour a ton of sugar on them, really just a light sprinkle is sufficient.
 - Don't say I didn't warn you.
 - I feel compelled to tell you, before you read the next exchange, that for reasons I cannot explain the box of Honey Nut Checks in the vignette speaks with a French accent.
 BONUS: Looking for a great late night snack? Put them in a bowl and cover them with a generous amount of lite Cool Whip. Give a very light mix and enjoy. Delicious and relatively lo-cal. You can send me a thank you letter in the morning.
 - Why not buy both, you ask? If I'm going to spend that much money, I'll just buy another box of Chocolate Chex. Or maybe a Wheat Chex if the mood strikes me.
 - By which I mean Wikipedia.
 - Wheat and Raisin Chex? Strawberry Chex?
 - Or was that visualization a little too much?
 - It's probably also why Honey Nut Chex still manages to sucker me once a year or so.