If you have mega men's sport and got it on discount, I would just use it. The best multi they have is ultra mega greens, though. It is also perfectly acceptable to take ultra mega greens and greens+ at the same time. (I do)
Mega Men Sport isn't THAT bad. The problem is that it just isn't the best. If you can choose between the 3, and one is slightly better while the other is dramatically better, why would you choose the worst option? Obviously if the worst option is cheaper, it has more appeal.
The main difference between mega men and mega men sport is that the antioxidant blend from mega men is gone, and replaced with an amino acid blend (amino acid blends in multis are basically useless, 5g of whey has way more amino acids)