What was Mark Morgan's music like, compared to Inon Zur?
you can call me biased, but i'd argue that mark morgan's stuff from the first 2 fallout games were some of the best musical cues ever laid down for a PC game. i'd rate it right up there with the score for 'outlaws', f.e.
a lot of the tracks were sorta ambient/atmospheric in nature, which suited the gameplay perfectly (i remember playing many a late night and thinking that the music just enhanced the imersion factor significantly). the tracks have a diverse amount of influences, be it tribal (worldmap, arroyo), eastern (hub), southern rock (car) and something i'd prolly have to lump in as techno for lack of a better term (new reno, vault city - i like techno, btw, but i understand it's not everyone cuppa.)
there was a soundtrack album released for FO1 (in very limited quantities -- many a long night was spent trying to snipe copies of it on ebay...), but ultimately, you could just extract the .acm files from your game disc and convert them into mp3s. some sites have put the whole soundtracks online for download (i won't put up a link, no idea how legal these are), but again, the score is really well worth checking out.
note: if you got FO1 only, you have 16 of the 24 tracks made for the series. FO2 recycled a lot fo the music and added 8 new tracks (what FO2 lacked in quantity, it made up in quality -- some of my favorite tracks are from the FO2 portion.) so if you got only FO2, you can get all 24 cues.
edit: well, i should talk a little about how it compares to the FO3 score (since that was the question, after all.)
basically, i'd summarize them as 'apples and oranges'. FO3's score benefited from the nearly 10 years between titles, imo. it's now a given that a game could receive a full orchestral score and back in the late '90s, that was most assuredly not the case (i'll discount the star wars titles that just recycled the original score music from the various movies.) i have no idea if the inon zur score used an actual orchestra or was simply created via a synthetic orchestra, but Fo1-2 most definitely take the 'digital mixing of various instruments/sounds/voices' approach that was common back then (similar, f.e. to the approach used for the scores for the first 2 diablo games, f.e.)
personally, i'd very much like to have 'official' score to FO3 (and not just a whole bunch of samples you sorta have to pick your way through.) that said, what i've noticed of the FO3 score has been fairly satisfactory. but i still find the FO1-2 score to be more impressive as a whole.