there are few draw backs with medicom:
1: generally smaller scale. this is something that all 1/6 company have problem with but medi seems to be making it more than others. Their RAH301 base is excellent but it is made for smaller person, that means noticeable shorter height and narrower shoulder. But it can work to their advantage as well when they make figure based on shorter actors in real life such as johnny Depp, luke skywalker. etc.
2: price vs value. Medis are import, and since they are japanese, the prices are high to begin with, and medi is notorious skimpy on accessories. (compare to others like HT and SSC)
3: sometimes questionable paint and HS. Medi generally have a cartoonish or some sort of anime influence with their HS, its not like the way HT or enterbay's approach, where they want to make their product as real as possible, medi is more on a different path, kinda like that's just their style of how they do things. And medi generally cast their head in the flesh color plastic and with very little paint, it doesn't show off how good (or bad) the sculpt is.
4: earlier figures have weak joints. A lot of people have complain their medi figure breaks too easily, (though I only experience that once, and the problem was solved in 2 minutes.) this seems more of a common problem with their earlier figures. The newer ones seem to have more durable construction.
That's about the gist of it. but seriously, medi has made many cool products. and IMHO, some of the best 1/6 ever produced. Get some and make up your own opinion. If you don't like them you can always sell them.