i had a conversation with a beek at the local beek association meeting about using all mediums. there are plenty of pros for the hobbyist, so i wanted to get a seasoned veterans opinion on some possible cons. he looked at me and said he'd tried it a few times and every time he got the same result - he killed his queens. for whatever reason, the shorter frames made it easier for him to get into the hive and look around and it afforded the queen less protection from being knocked off the frame, esp. if she was closer to the bottom.
i asked another well seasoned beek who does the Q&A sessions at the local beek association and he said he had a tough time with over wintering - they have to break cluster to move between the boxes. he lost his medium hives while his deep hives over wintered with no problems. he also had problems with swarming - he thinks the crossing between boxes led to an overcrowded condition.
sure it's only two people, but these guys have been beeks for 30+ years each and have tried just about everything. they said since my plan is to only have 2 or 3 hives to just stick with deeps and use mediums for honey supers. you get more honey per frame so you need less boxes.
seems only 2 or 3 people are using mediums brood boxes in my area and they seem to be ok - i decided to stick with convention until i have a few years more experience of "traditional" management under my belt. i had to deal with a swarming situation my first year as a beek, i don't want to have to work all that much more to prevent it. maybe in a few years i'll give all mediums a try, but right now, i'm happy that things are working - ain't broke, don't fix it.