IMPs are far better than any MRE. They are extremely expensive though unless you get really old ones from 5 years ago. I would eat an IMP if it were 2006 or 2007 but that's it. And I'm only saying that because I have one in my fridge, I skipped my last field lunch on BOTP to take the IMP and the good chocolate bars the lunch ones always have. There's no way I'd ever pay cash for one.
That said, a burger beats it out, hands down