Note that Tramadol has the antidepressant, from what I understand Ultracet does not. They're both just the same core drug.
Personally, I can't feel ANY effect from them in comparison to Vicodin or Norco, outside of nausea.
happypill:
Think of it like this:
Vicodin hits portions 1, 2, 3, 4, and 5 of your brain. All 5 do different things (make you feel good, slow down your breathing, etc.).