although i haven't taken the MCAT yet, i do have the EK AO cds. my assessment is this: if you can get them used (or free, as i did) go for it, but otherwise, paying $200-$300 for something that's really not a primary study aide isn't worth it. i, like you, have a long commute to school/work, so i figured, "why not make use of this time by drilling myself with acid-base chemistry and electromagnetic forces instead of rocking out to music that i actually enjoy- which keeps me from murdering people?"
bottom line: its nice as an inexpensive supplement to your studies, but don't shell out big bucks and put all of your eggs in that basket.
redundant disclaimer: i have NOT taken the MCAT yet, so who knows, EK AO may be the best thing since sliced bread (or internet porn, depending on your tastes...)