Big shot is substantially heavier. At the lowest flame level it is maybe a bit bigger than Big Buddy lowest flame (possibly 20-30% bigger, not sure though).
The flame is constant and strong as long as gas is high enough. I aim for minimum possible flame to save gas. Safety wise dont see either a problem for long running, it is what they are designed for.
Build wise, Big Shot is superior, stronger, sturdier. Also more stable, so probably safer in that sense. But being more bulky, maybe more chance if accidental error some day, placing down alight etc. Needs a bigger space.
They do perform differently with the Elev8r. Big shot does heat a little more aggressively, Big Buddy a bit more gentle.
I personally struggled with the Big Buddy due to hand/wrist issues and being prone to repetitive strain injury and tendonitis. The Big Buddy torch was a real problem for my hands because you have to hold the ignition button in with one thumb which takes quite some force while you lock the continuous flame switch with the other hand.
So I made an arrangement with vapefiend for me to exchange the Big Buddy for the Big shot.
For my hand and wrist structural weaknesses the Big Shot is excellent when it comes to igniting- couldn't be any easier or more gentle on my hands.
The only thing I don't like about it really is the heaviness and bulkiness factor. But this is the only torch I can see myself being able to use without messing my hands up for now.
I would say that the Big Shot is worth the investment because it is just better made and the Big Buddy felt a little finicky and prone to breakage to me. But it works very well and very many people are using this torch and are completely happy with it.
Both good torches. The Big Shot definitely rocks a bigger flame especially when you turn it up but do keep it in mind that most of the videos you will see do have the flame turned up a bit to show the potential of the torch.
Not sure what else to add now but I hope that is of some help and have a nice day.