My experience was quite different than most people that go with premium heavy duty clippers.
I have tried a few different techniques with our standard 70 lb bernedoodle. I really think that your needs will vary quite a lot depending on the type of coat your dog has. Our dog has a very thick coat of fine soft fur. I used to use scissors for her, but now I have converted to clippers for most of the job, and just use scissors for her face, and a little bit of cleanup.
My experience has been that an inexpensive set of human clippers (here:
https://www.amazon.ca/gp/product/B004OL3QES/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 )
does a great job.
I use a snap-on plastic comb (5/8 inch). Most people will say that this clipper is too lightweight and that a plastic comb will not do a good job - it will fall off, or it will get caught, the clippers will bog down or overheat, etc. This has not been my experience. I found it works fine. As long as the fur is fairly clean and *very* well-brushed, it works great. I keep on top of it by grooming her every 2 or 3 weeks rather than waiting for it to be a big job. She lies on her side and I do one side, and then then I roll her over and do the other side.
As a matter of fact, I borrowed a pretty expensive set of clippers this past weekend to compare. It was much heavier and more powerful than mine, and had less vibration. I did not like how heavy it was, but the low vibration was a nice thing I guess. It had a #4 blade on it - so it should have been pretty similar. Thing is, a blade is fairly fine, whereas a snap-on comb is widespread. Long story short is that I could not use that expensive set - it was terrible - it was like trying to run through her coat with a very fine toothed comb, whereas a snap-on comb on my clippers was more like running a wide-toothed brush through her fur - it glides through. I just run it through a few times - against the grain - and it provides a pretty even and nice cut.
Maybe using the heavy clippers with a snap-on comb would be a little faster, but I am not going to bother.
Again, I think it really depends on the type of coat you are dealing with.