It's a great starter set to get into the Milwaukee brand but is definitely not the top of the line. From all the reviews and youtube videos I've seen it's actually a great entry for the DIY, casual user that doesn't need a professional set.
From what I've seen the difference in power between M18 and M12 (Fuel) is minimal and comes in play if you are a professional. There is a big difference from M12 Fuel and M12 regular, but the price for tools double if you go with Fuel. .
M12 Fuel: Brushless & smart controller (intelligent power delivery) - Big cost
M12 (regular): brushed and slightly less power - Low cost
My strategy was to pick-up this M12 combo so I could start with Milwaukee. I would buy batteries that are compatible with M12 Fuel and replace the tools with M12 Fuel models as they wear out or don't meet my demands.
I also considered Dewalt but choose Milwaukee because of the strategy of Dewalt to mass produce and gear towards end user, vs. professional user. The main motivator for Milwaukee was their focus on automotive tools vs. Dewalt's focus on construction. I actually already bought the M12 Fuel torque/impact tool and it was $150 by itself on sale.
Just my $0.02.