My family moved several states away 3 times while my sisters and/or I were young. On one occasion I was between 2nd and 3rd grade, on another my sisters were between 2nd and 3rd and 5th and 6th, respectively. On the whole, we turned out fine; eventually made new friends and all that, not scarred for life. Middle sister had a lot of trouble with that move between 5th and 6th, but I think that had more to do with her personality than age. She was the most introverted of all of us and had one really close friend through elementary school that she had a hard time leaving. But even she made new friends eventually...and ultimately applied to, got into, and made some really solid friendships at a math and science magnet boarding school at the new location. Your kids will have an even easier time because at 3 hours away and with family in the area you will visit all the time (at least at first, you'll probably taper off as you put down more roots in Pittsburgh).
I would definitely price out the 35% pay raise against cost of living (probably dominated by housing), any lost income from your wife while she looks for (new?) work, childcare if family used to help out, etc. There might be other reasons it makes sense for you to move even if this is a net loss in time and money...maybe this intense job is a great career step for a much higher-earning or flexible career in a few years? Maybe it's just infinitely more interesting for you (now or later) and will keep you engaged/energized rather than kill your soul like a bad-fit job. Maybe the 'burbs can offer your kids greater educational, cultural, etc opportunities that you would like to give them. On the flip side, perhaps it's not worth it for you. Maybe the higher paycheck doesn't compensate for longer hours and higher COL, the job doesn't necessarily lead to anything you want, and you prefer your small town to the suburbs. Maybe you don't move.
I'm going to disagree with mxt0133 and say don't ask your kids if they want to move, tell them if you are moving, as a fact. Do talk about their feelings on the subject, give them plenty of time to adjust to the idea, say goodbye, etc. But don't give them the false idea that it's up to them in any way if you move or not.