I don't know a whole lot about Hinduism, as I've never studied it in depth. But having a God of evil or terror does not in itself make the religion hideous. After all, you've got one of those, too (Satan). The evils which the Hindus attribute to their evil gods are the same evils you attribute to yours, generally, I think. I'm sure there are subsets of the Hindus who worship those Gods. There are also Christians who worship their god of evil (i.e. Satanists, who are a subset of Christianity). The gods of evil and destruction in Hinduism also have their good and beneficent counterparts, as does Satan in Christianity. Really, the only difference I see there is in numbers. They have many of each, and you have one of each.
Karmic Law is simply the idea that you get back what you give. If you do good, you get good in return. Do evil, get evil in return. What comes around goes around. The Golden Rule. Etc. That's Karmic Law. Not all religions that believe in Karmic Law take it to the extreme that Hinduism may, with an endless cycle of reincarnation.
Speaking of reincarnation, just remember that you don't have any real evidence that it doesn't happen that way. I don't count teachings from a holy text as evidence. I'm not saying that I do or don't believe in reincarnation. I make no commitment on it. I've heard several afterlife theories, from reincarnation to heaven/hell, and so far no one has shown me anything to nudge me more in one direction than another. I would almost say that what little empirical evidence there is of a possible afterlife favors at least some notion of reincarnation.
