I try this from time to time with Jessica Seinfeld's cookbook Deceptively Delicious. I think it's all good but when you cook the veggies twice for her recipes (purees and then into food), I do think you lose most of the nutritional value.

My nutritionist says kids have to try foods 25 times to accept them. I have noticed that this has worked.

Personally, I'd do both.

Yeah, you know I read somewhere that kids do need to try it a couple of times - well more of a lot - before they accept it! Will keep that in mind.

I love adding veggies to recipes. I guess I am lucky my guy really likes them.

I try not to have to "hide" veggies; I'm lucky that our kids tend to like most veggies they try.  I have, when they were younger, smashed cooked carrots into the spaghetti sauce, just to add some more veggies to their meal. 

I sometimes hide veggies in foods, but I always offer some on the side, too.
I have also found that some of my kids prefer their veggies raw instead of cooked. When I make steamed carrots or broccoli, for example, I will leave some out and serve them raw to my lil' girls.

Another idea is to try different fruit and/or veggie "salsas" they don't have to be spicy. A lot of kids like to dip things, that can be a healthy alternative, and might be just different enough for them to try. 
Some kids, no matter what you try, they just won't eat the veggies. *sigh

I think adding veggies to  recipes is great, but it shouldn't be the only way the kids eat veggies. 

I have five children and one that is extremely picky... I add veggies to my spaghetti sauce and it cooks for a while so they are small and soft she doesn't know they are there and eats them right up, I have also started adding them to mashed potatoes and she knows this and still eats it because it is cool that it changes the color of them. I think that up to a certain age it would be okay to do this just to keep from the arguing but after a while it is better they at least try them.. even if it is when cooked a certain way. I would be more than happy to share my recipes with any one also.