chinese drums can be kept fully loaded indefinitely without weakening the spring inside because you only wind the drum up when you're ready to fire. the romanian ones don't have this ability - when loaded, there is full tension on the spring. over time this may cause the spring to weaken so it's probably not a good idea to keep a romanian drum loaded over the longer haul.
so with a chinese drum, you can have a fully loaded drum on standby in your rifle and have the drum operational in seconds merely by winding it up. thats a main advantage bewteen the two.
another advantage of the chinese drum is how simple and fast it is to load. you open the back up and "drop" the ammo in wherever it fits. with practise, you can load a chinese drum in under 30 seconds. the romanian drums require much more effort to load as they have a lever you will need to continually press down each time you load a round - and it will make your thumb a little tired sore at the end. since you have to put the ammo in one at a time from the top- obviously it takes quite a bit more time to load a romanian drum that a chinese one. thats another advantage of the chinese over the romanian. One last advantage of the Chinese drum lies in its upwardly moving resale value, as these cannot be imported any more, so they could make a good investment, as they won't lose their value. On the flip side, there is no import ban on Romy drums - so if a ton of Romy drums were to flood the market by chance - most likely the price would drop and thus, they could potentially lose a little bit of their current value.
There are some advantages of the romanian over the chinese drums. first off the obvious - price. The romanian 75 round drums are on average about $30-$50 cheaper than their chinese counterparts. Another advantage of the Romanian drum is that the overall construction is somewhat "beefier" - with the steel being thicker which makes it a bit more rugged and more solid than the chinese drums. So , it's a little harder to accidentily "ding" the metal on a romainan drum
for this reason. Also, on the chinese drums, the hinges and spot welds are a little more flimsy than that on the Romy drums.
It should be mentioned that both the Chinese and Romy drums when loaded rattle quite a bit when you're moving around. I have both types of drums, and I'd say the Chinese drum is MUCH noisier that way than my Romy drum - so that could also be another slight "tactical" advantage of the Romy drum over the Chinese since such a rattle isn't going to help you to keep your cover so-to-speak. People will hear you coming as the rattling of the ammo inside can be quite loud.
Both Chinese and Romy drums are really considered to be a "novelty" more than anything. They are both not really that practical in combat situations. Some may disagree with that. But just read what I said about the "rattle" above for more of an idea on this. All in all, It's really the overwhemling "coolness factor" that makes these drums so popular really. With the steadily upward increase in interest in AK's and recreational shooting occurring over the past years combined with the high interest in the AK pistols that have come out - interest in both kinds of drums is on the rise, and so, through supply and demand, the prices continue to creep upwards.
Hope this helps.
-Jamie