How bad is it? Imagine an after school special with Jesus, porn and blaxploitation.
Should you see it? Yes, but don't expect much.
There's a version of this that doesn't mention the alien factor on the cover, but a very obvious Christ-like alien comes to Earth, specifically to the tough inner city streets, where latino gangs and black bad guys (who seems to have more money, power and style than the others) control things. The alien fights the bad guys, but violence saps his powers. He teaches kids to read. Then he has them create positive message graffiti. He has them build a car out of scrap from a salvage yard - for his use! There's about four rapes, some breakdancing and ending a fight by punching a sign. It's so wrongheaded in so many ways, doesn't know where to go or what to do and preaches to the audience a message that may not be intended (i.e. only a white guy can save you).