Hi, Im not from US so it might not be the answer you are looking for but since Im pursuing my MD I might be able to give you some answers:
a) how difficult was to get in? rather easy, we had a test at same level as were our finals and while some did poorly we all got accepted because the course could support that amount of students (its me and 4 mates so its rather family like atmosphere)
b) expectaions: Im not sure, its just a something I need to have to be accepted into phd program so I was expecting that I will improve my knowledge of ochem and lab practice and so far both worked nice, although my ochem knowledge could be better probably if I worked bit harder
c) exams: probably the biggest change, its no longer 60% to pass or something like that like was in undergra but rather its a starting point for further oral examination (ie. the better the test the easier is the oral exam but you can theoreticaly pass the oral when you have realy bad written exam)
d) workload: depends. last two months I was in a lab basicaly every day for 4-8 hrs. I also run into the lab in the pause between lectures because I needed to run a HPLC sample, or being in lab early so I can filter and dry my product to work with it later in the day.
We also have to have a short presentation in front of basicaly whole department and comitee about our work each semester to get one of the classes done. Im not sure but I think that two guys didnt pass because they didnt do much work in a lab
e) thesis, since we wrote a thesis in undergrad its basicaly the same but more in depth, some 25 pages of literature search and introduction to the topic for a reader and maybe 40 pages of experimental work are expected. But it depends on what exactly are you doing (ie. probably hard to fill 40 pages if you ran in-silico but you can be close to 100 if you do solid phase combinatorial chemistry for example).