Pentacel works best for our current schedule (DtaP, Hib, Polio) with Hep B separate but we are considering Pediarix for our new baby if GSK's new Hib+ Men C vaccine comes out; then we would do Pediarix + that one and be almost done.
My investigations of both Pentacel and Pediarix have left me thinking that they are good options for our family. There are good immunity numbers, not too bad reaction numbers (pentacel slightly lower than pediarix it seems), and they really cut down our shot numbers which means less pain. There does not seem to be the issues MMRV has with fever either (for either combo shot).
Also both demonstrated fewer fever reactions and less crying length than the individual shots they are made of in clinical trials.
That's good to know! I would consider Pentacel if she were younger, but at 2.5 years old (just getting started with vaxing) she only needs 1 Hib. Its such a tough choice; I'm willing to make the extra appointments and co-pays to space the doses out... but I am also concerned about how she would emotionally handle that many injections, kwim? Plus in all honestly I'm still rather shocked that we're going to be vaxing at all I thought we'd closed the door on that one a long time ago.
I tend to want the minimum number of diseases at a time that I can possibly get, so I wouldn't go for the combined shots. Of course, we also end up with fewer injections, because we don't do all the doses or all the diseases. HepB, for example, we skip entirely.
You might want to look into the ingredients of the brands you're considering, especially their thimerosal and aluminum contents, that could help your decision.