For me it is completely hinged on what list i am playing.
My Vanilla Marines have 6 Drop pods in it. 4 for Dreads 2 for tact squads. But this is an in your face list.
My Wolves get all Drop Pods, Cause I like to get into the thick of things.
My Gun Line Marines get all Rhinos each.
I prefer Drop Pods over Rhinos mainly cause they are tougher to destroy because of AV 12 all around, but also during objective based games I'll try landing on them to tie up a round of shooting or combat by the opponent trying to remove it. I also get the fortune that occasionally people forget that it can contest an objective or table quarter. The downside to this is you give up the kill point.
The Drop pod gets you where you want to be but only once but is tougher.
The Rhino will most likely get you where you want through the game. And is good at making late game grabs on objectives. The downside to a rhino is if it gets popped before getting across the board then the points may have been wasted because you now have to slog it across the field. But by the same reasoning it saved the unit from taking the shot taht destroyed the rhino.
Just my two cents!
The footprints made in the sands of time are not made by sitting down... Unless your playing Warhammer WAAAGH!
New times calls for new Records:
Orcs & goblins (3-1-2)
Imperial Guard (0-0)