Seriously tho, this is little bit of advice completely revolutionized my diet. Also, since the frozen veggies are already chopped/peeled/etc, it speeds up meal prep a LOT -- useful on those busy days.
The best thing about frozen veggies is the various mixes you can get. I usually buy a giant bag of brocoli and then a giant bag of whatever mix I'm feeling.
Boiling in water seems to be one of the worst methods, which makes sense because the water can easily leach all of the nutrients[1].
Everyone does agree the best way is simply to steam them.
[1]http://www.associatedcontent.com/article/250016/how_to_cook_...
A recent study conducted in the U.K. showed boiling vegetables that are members of the cruciferous family, including cabbage, broccoli, and brussel sprouts, significantly reduces their anticancer properties.
And MW specifically
If you choose to microwave your vegetables, use as little water and as short a cooking time as possible to minimize loss of vitamins.