It all depends on what you are trying to prune. For smaller branches up to around 2-3", a manual pole pruner with a saw blade works great. For slightly larger branches, a cordless pole pruner with a chainsaw bar would work well. If the branches are much bigger than 5-6", a cordless chainsaw will handle the work easily, but branches that big can be difficult and dangerous to prune if you've never done it before. The idea that a cordless electric chainsaw is somehow safer than a gas saw is completely false. It's still a very dangerous tool if you don't know what you're doing.