I personally believe that Lego is not as efficient as Blockland. Although Lego can handle more complex pieces, because, well, it's physical, it's physical so that it costs money. And the more complex the part, the more it costs. Blockland is not as expensive, in the long run, even though Lego is easier to show off. I just can't imagine any way of making any investments into legos while still having fun doing so. :P
..But Legos are still fun, don't get me wrong. I love Lego. :)