I am not going to start on One True Way versus Hard Style or whatever. Just an observation after abstaining from timed sets for over a year.
During my las session the day before yesterday I did 32 reps per hand with 16 kg bell in 8 minutes (after doing 8 minute set of alternating snatches and swings). Surprisingly, I managed to complete it, even though at this moment I am completely untrained for this activity. Not a great weight and not a remarkably high cadence either. However, after the set I was dripping with sweat and my muscles were trembling. These sets also required some mental effort. Not too grueling, but noticeable.
Which brought me back to the whole debate regarding timed sets, girevoy sport and hard style. HS guys insist that they purposefully keep the technique suboptimal in order to increase the training effect. So any effort to save energy should be dismissed.
I am not aware of any study - and there probably aren't any - that compares energy expenditure of HS snatch versus that of GS. I still suspect though that overall effort during timed sets is going to cost more in terms of oxygen consumption than the cumulative cost of several HS sets. There is something about continuous work that makes it special. Twenty squat routine, for example, is very well known to bodybuilders, and it gives compares fairly well with GS sets in terms of effort. Squatting 70 kg for 4 sets of 5 reps is relatively easy, but doing 20 reps non-stop gets you seriously winded. GS sets are similar, and I think from metabolic point of view they are very demanding.
Which brings us to another point that I have maintained for a long time: you don't have to do 10 minute sets every time you train for GS. Exactly because these sets are so physiologically demanding they should not be done too frequently. Just like maximal lifts in powerlifting or full effort long distance runs.