I agree with Sushi (what type of sushi I wonder though) but I'll try to give some more details and examples. Lucid dreams can be a lot, for the most part it is what you make out of it, but there's always this kind of mysterious factor given by your subconsciousness. And often you can consciously draw out this factor and experience totally new things. Most lucids, especially if you start will be hazy and though you might know you are dreaming, you might not realize it. But your level of awareness can also reach new heights, with new senses and totally new feelings and experiences real life doesn't offer. Though a dream will likely never feel like real life, it might just feel even more real in a way or simply different but dreams tend to always keep something distinct about them, not a bad thing in my book.
I'm not saying imagination is the only limit, but there aren't many more limits out there, and a lot of these other limits can be crushed in one way or another with enough time and commitment.