Each alliance offers different advantages and disadvantages, partly because they are looking for different customers and cater to different home markets.

None are perfect (they do exists to make money after all). The one you choose will depend on where you're based, your travel patterns and what your priorities are. My priority is getting Emerald status in OW and the advantages that gives me. Frankly, I don't care too much about the miles restrictions because most of my longer flights are in Business Class.

If mileage accumulation is the main priority for you, work out where you want to fly, and then choose the alliance that will give you the most miles for doing so. It's that simple.