My current guilty pleasure where science fiction is concerned is the books of John Ringo. Among other things, he writes the sort of books that can generally be summed up as "evil aliens attack Earth (or local equivalent), plucky humans kick their asses then weld a reverse-engineered warp drive onto a U. S. Navy submarine and head out to conquer the universe." They aren't particularly deep and they do have a number of flaws -- for example, the military jargon is often baffling and it's sometimes difficult to follow what's going on, to the extent that there were times during the middle of the Posleen War saga that I pretty much had to sit back and let all the noise just sort of wash over me until I saw some recognizable character on the shoreline two chapters later. Also I think more than one minor character's name changed spelling halfway through the story. But on the other hand, it's clear that he is having a hell of a good time writing these things. That counts for a lot, and by the time he's got a three hundred foot long nuclear-armed tank with Bun-Bun from Sluggy Freelance stenciled on the front bumper crashing across the Tennessee mountains wiping out alien invaders by the thousands you pretty much just have to smile and decide to roll with it. Think Transformers 2 and you're really not far off the mark here.
I do also have to say that while Ringo's characters are generally cut from the finest cardboard, they're still enjoyable to read about and often sport a refreshing refusal to take crap that is rarely seen in more "standard" SF and fantasy. I can't help but compare Ringo's books with something else I've read recently, Tad Williams's Otherland series. One of Otherland's more aggravating features is bad guys who get their way simply because whenever they show up our heroes are too overwhelmed by despair and hopelessness to respond. Dulcie Anwyn may be a much deeper character than Cally O'Neal, but on the other hand Cally O'Neal would have put a .45 round between that twerp Dread's eyes the moment he dared to threaten her life instead of turning to jelly, and the series would have been at least a thousand pages shorter. There is something to be said for that.