When I first began buying bulk lots I got caught with a lot of Megablocks once or twice, so there have been many in my house. I discovered the difference when I began cleaning the bricks and the megablocks all began to float, while the lego sank to the bottom - density and quality may have a correlation.
When I have excess MB's I bag them up and give them to kids at pre-schools or other places that don't have any blocks to play with.
The concept of the brick is a great one for learning and developing motor skills and once these guys get old enough to discern, they can make their choice.
I will keep tyco in my collection to help build interiors and supports, but I find megablocks too inconsistent, so put them in my give away pile.
I will admit to having some of the megablock weapons, but find they distort the lego hands - much like the work of Sauron ....
Those that can - build with what they can afford.
Enjoy the brick for what it is worth.
I prefer Lego.
Bert.