I prefer the gnostic take on it: the wrathful god and the benevolent god are actually two separate beings.
But to address your question, well, it's complicated. Personally, no, I don't believe in a God like you describe. But as a non-Christian, I don't need to.
Modern Christianity is the great-great-grandchild of Judaism. Proto-Judaism was born of a sect of Semitic peoples that moved away from worshiping all the gods in their pantheon, and moved to worshiping Jehovah above all others, and then to worshiping Jehovah exclusively. Along the way, they purged, again and again, their beliefs and holy texts, but some hints remain. In Genesis, God says something along the lines of, "Let us create Man in our image." Originally, he would have been talking to the other gods. Genesis, being one of the older books, was probably written when Judaism was still transitioning into a true monotheistic religion. Consider that the commandment is to, "Take no other god before me." According to the Ten Commandments, it's ok to worship other Gods. It's just that if there's a conflict between what Jehovah says, and what another god says, you have to follow Jehovah. There are other hints too. There are two completely different creation myths recorded in Genesis, one right after the other. It's pretty clear that things were in a flux of some sort when this was written down and recorded as "literal gospel truth".
Pottery sherds have been found in the areas that we believe that the proto-Jews lived. Some of them have writing on them. And some of those refer to Jehovah's wife. There is a whole body of evidence that in the original myths, before the Jews learned to write, that they believed that Jehovah was married to Asherah, one of the Semitic goddesses.
So, we have an originally pantheistic pantheon, where the other gods have been written out of the myths, leaving only Jehovah. He had to encompass new roles, new stories to do this, which can help to explain the two faced nature of the Jewish god.
At the same time, out modern belief systems have vastly expanded over what they originally believed back then. We have greater imaginations and greater abilities to envision great or powerful deeds. We've grown philosophically too. So many of the myths, as written, seem off to us today. Originally, three thousand years ago at the origin of Judaism, writing was rare. Education for anything other than a tiny portion of the populous was impossible. Priest-kings or God-kings ruled nearly the entire civilized world. They struggled with the ideas, but there was no need to weaken their power base by putting those theological and philosophical questions before ignorant and uneducated masses. Today, nearly everyone has a basic education and the free time to explore these questions.
You have myths in the Bible, such as Jehovah telling Abraham to sacrifice his kid on an alter. And Abraham started to do it, and then God is all like, "Nah, I was kidding. Hey, worship me, I'm so cool that no one has to make human sacrifices anymore. Isn't that awesome, and better than all those other religions?"
On the surface of it, it sounds good. God is saying that we don't have to do human sacrifice anymore, like they do in the next valley over where they worship snakes and that flying man headed lion thing. But if you dig a little, you might ask if God's a dick for asking Abraham to do something like that. It seems like a cruel joke to pull on Abraham. So, what does it mean? A gnostic might say that it means that it was the evil god that Abraham was talking to. Someone else might say that Abraham failed a test by trying to sacrifice his kid. Others might say that God was the one that failed the test. But maybe God learned something, and got a bit better. You know, change and evolve with the times. The "true answer" depends on your vantage point and what theology you believe in. Of course, a changing, evolving God is an ill fit to a God that has a cannon carved in stone that can't be changed, that keeps pushing people toward the nearly caveman views that he had a thousands of years ago.
Then you get into things that just mean different things now than the did back then. When we hear that Jehovah's "all-powerful", we have a conception that means that he can change the nature of reality on a whim, alter the gravitational constant of the universe, make water burn at room temperature without changing it's chemical formula, violate the laws of thermo-dynamics, and so forth. We can conceive of those things, because we have a much bigger idea of what the universe is today. But three thousand years ago, (most) men thought that the sun revolved around the earth. We thought we were the center of the universe, that nothing else was more central than us. We didn't know that our sun is like a grain of sand in a universe that makes the Sahara desert look small.
When the ancient Jews said that God was all powerful, they weren't saying that nothing is beyond God's ability. No, they were saying that no one is more powerful than God. They did not have the concept that god was boundless. He has to work within confines.
When the ancient Jews said that God was all knowing, they didn't mean that in sense that we think today. They didn't mean that he could see all of time, that he knew what was going to happen thousands of years in the future. They didn't mean that he had an infallible knowledge of all things. Instead, they meant that he knew everything that could be known. That there were things that were even beyond the God's ability to know.
When they said that God is good, they didn't mean that he was some platonic ideal of all good and nothing but good. They meant that he was a good guy. Better than us mere mortals. But they didn't have this idea that God was perfect, just that you couldn't be better than god.
There are passages in the Bible where people argue with God, and win the argument. There are times when God changes him mind. There was an occasion where God was going to kill Moses when he was a teenager, because he wasn't circumcised, that that's gross. So God comes down in all his fury to kill the kid, but Moses's mom quickly grabs a knife and cuts off Moses's foreskin, and then throws it at God. God goes, "Eek!" and jumps back. And then he says that Moses can live, and he goes away. So, his mom actually beat god. And it's in the Bible.
The story illustrates that the notions we have today of the Bible saying that God is Omniscient, Omnipotent, and Omnibenevolent had very different meanings back then than what they do today. By today's definitions, of Omniscience, Omnipotence, and Omnibenevolence, you can pick any two and have a being that isn't a logical contradiction, but as soon as you add in the third, you have a contradiction - a lie. If God's all-knowing and all-powerful, the world makes sense if God's a dick. If God's all-knowing and all-good, but only has a limited amount of power, the world can make sense; it would be beyond God's power to stop all evil. If God is all-powerful and all-good, but not all knowing, than our world makes sense too; God means well, and can do all kinds of miraculous things, but sometimes things go wrong (like that whole creating Lucifer bit).
On the other hand, if we don't take Omniscence, Omnipotence, and Omnibenevolence to be as powerful as the modern definition, than God and world can make sense. God is powerful, but he can't juggle galaxies, eat black holes, change the nature of water... he's really smart, but doesn't have perfect predictive powers so he doesn't know that Lucifer will turn against him at unleash evil on the world... and he's good, but you can still piss him off, and when you do, whoa, watch out, he might just wipe out every single one of those evil bastards in the next valley over, even the ones that weren't really all that bad.