I have read the LOTR and Hobbit both now, and in terms of complexity of story, there is no comparison, LOTR is much better and has richer characters - The Hobbit is more of a straight out adventure story, no romance, no high emotions, etc. However, I have heard that they are going to do two movies, and will add a lot of stuff for the second movie that isn't in the book, I guess we will see.
True, the LOTR is at a higher level, but the Hobbit definitely changes tone through the story. it goes from almost a "fairy tale" like beginning, with the meeting of the dwarves and the comic-like encounter with the trolls, to the more serious encounters with the goblins and spiders, a bit more serious with the dragon, and finally the war at the end is almost "LOTR-like" with Bilbo sacrificing for the common good.
LOTR definitely goes way beyond that, but at the same time the lighter tone of the Hobbit is almost a nice change of pace. I like the LOTR better, but the Hobbit is funner and a whole lot less heavy, so there is that. I am just glad that another couple movies in the franchise are coming out, mostly.
Growing up, my favorite book was LOTR (still is) and I also liked Spiderman from the comic book world. My childhood choices in entertainment have been greatly validated by movies in my adult years, lol.