Well, this is a vary vague, yet sort of justified question for those new to slingshots. I think we need a few more specifics though...
What are your priorities, because with all slingshots there is compromises...You cannot always have MAX speed and power and have long band life. And long band life usually doesn't mean the most speed and power. And these generalizations all correspond back to the type of ammo you are using. Some bands just do better with heavier ammo to avoid hand slaps, wild shots etc.
A few questions, I could take 30 minutes to sit down and type to explain some things to you, but I don't plan on doing that so help us out a bit here....
What are you going to use your slingshot for?
Do you have a budget for buying bands and then buying the ammo, or scrounging it somehow that does best with your band configuration, because you said best?
Do you have a preferred draw weight, light. medium, heavy....more specific actual poundage, etc. ?
How long do you want your bands to last for?
Will you sacrifice longevity for a little more speed?
These are ALL generalization, there are really no borders like I have basically drawn up if you have the right mindset, skills, ingenuity, and materials. There are slingshot enthusiasts who have broken these barriers in the compromise between speed and longevity...but it is a little harder for the average newbie to the hobby.
Answer us a few questions so we have a better idea of what you are looking for and then you'll get some great advice.
I use slingshots for minimum coffee can destroying and mainly hunting. There fore I like power with very heavy ammo for devastation while compromising for longevity. I want bands that will last through practice sessions and a long hunt with no worries.
At this point that job falls on a few band sets.
- My trusty chains that are cheap and easy to construct and they last pretty well and when they brake the change is easy.
- Round solid latex cordage which lasts forever and is cold resistant and capable of hurling my stone ammo (free!)
- Heavy double tubes from Frogman, hefty draw yet is the fastest out of all of these hunting options. And they will likely reach the thousands in shot count with ease.
- Finally, the hollow forever tubes that have a nice smooth draw with some heft but fire lead very well and were recorded to last around 2000 shots
As you can see I value durability and the ability to shoot my stone ammo which is unlimited and free.
Hope that helped a bit, good luck, maybe when I have some more time I can elaborate further and cover more bases, but other members will do that for me I'm sure.
Cheers - John