Two unique ideas that Mr. Cossman has, and actually no one has repeated, is the offset guide and the graduated saw.
The offset guide compensates the cut on the half pins on the ends by the thickness of the saw, his saw that he sells. But that thickness is pretty close to almost every other saw.
The graduated saw is a saw in which the first couple inches are have a lower teeth per inch ratio, making it a coarser blade and rougher cut, which in his estimation makes it easier to start the cut without the saw bouncing off the wood. I never had a problem with this, so the saw is a solution for which I had no issue or problem.
I like his videos and techniques a lot.
That said, I learned the Paul Sellers method at the school where he taught for over a decade in Waco, Texas. Its a much simpler and faster method.
On thing to thing about is a dovetail alignment board. Sellers just uses a hand plane to support the top piece for scribing, and one relies upon a good eye and perhaps a straight edge to keep things square. Jonathan Katz and others use, and sell, 8x10 board which has a lip on the side which keeps the tail board aligned with the pin board for scoring.
I disliked every dovetail guide made, like the Katz Moses guide and others. They are slippery and hard to hold onto the wood, and although some have magnets, to hold the blade onto the guide, I found them annoying.
Bottom Line for Me:
I'd start with Paul Sellers and make a simple wooden box using his method out of pine. This box was the exact box we made on the third day we took the class to make dovetails through the Paul Sellers method.
https://www.youtube.com/watch?v=9EqgMx7fvls I think you'll find that his method is good enough, especially after gluing and finishing the box, as any imperfections are either not noticeable or add to the character of the box. One caveat--pine can come out in chunks if the chisels are not sharp.
Next, I'd try making the same box using Rob Cossman's method using his offset guide and perhaps his saw. You might try a dovetail alignment board on this second box.
Then, I'd figure out which one you are more comfortable with.