While Leatherman, Gerber, and SOG are all excellent multi-tool companies, they typically shine in different categories.
Leatherman tools are generally considered the best quality and offer the most functions, with SOG considered as the highest the best Tactical Knife Multi-tool, with Gerber winning in terms of the best value multi-tool.
As with many purchasing decisions, the real question is what tool functions will serve you the best, and of course, your budget.