Microwaving vegetables destroys a lot of the vitamins and almost all the antioxidants in them.
Yet its still better than raw veg, or no veg if the easyness and time saving makes you more likely to eat some rather than none.
Also, for instance that new scientist link, simple says it destroys more nutrients, it could be that microwaving kills 7% while steaming kills 5%, its still more, but not really a noticable of significant amount. It could be much worse, or not, and it lists the cause as largely down to the higher temp it hits. Does cooking on lower power for longer solve the problem, then what happens if you overcook the veg in a pan by a minute, same problem?
I've had a few of them before because, when you're trying to eat 6 times a day I was simply spending so much time cooking, cutting veg and so on that it became a pain and buying so much fresh veg I was running out of fridge space, and a missed day of eating much veg and I end up with some veg thats not very edible so frozen premade bags were fairly useful and certainly better than just not eating veg.
However, the bags normally don't have great veg in, aren't cut equally so don't cook very even so wouldn't taste great. oh well, I tend to try and just cook a massive batch of veg in a massive pan, nice stirfry then keep a huge tub of it in the fridge, and reheat a bit a few times a day with whatever food I have. Seems most convinient, cost effective, tasty and healthy way to cook veg.