I'll weigh in on the other point of view!
We have stayed at both resorts - stayed BWI concierge and in all room types at the GF, including 6 stays in LV. I have two children who have been going to Disney since they were 4 (now 13 and 15) and we've taken our nieces at various ages.
Our vote would definitely be the GF! My kids love MK and the access to it from the GF cannot be beat. Bus service to the other parks has always been good as well. There is the convenience of Gasparilla's Grill to feed the kids and several table service restaurants to choose from. And of course all you need to do is hop on the monorail to dine at the Poly or Contemporary. You can also easily take the monorail to MK, get off and catch the boat launch to WL where there are also great dining options.
You can watch Wishes from the boat dock and see the Electric Water Parade right from your LV balcony. The two pools are great - and both offer different atmospheres. The GF lobby and shops are fun to explore as well.
We have stayed at GF 8 or 9 times and have always had great service though I am a bit proactive. I call every morning and request that our room be cleaned by 1p.m.since we like to return for afternoon rests. And I also request a specific time for turndown. I tip accordingly
We love the atmosphere at the GF - it has a quiet, peaceful feel to it which is so welcome after the frenzy in the parks. We enjoy the Boardwalk area but it has a definite energy about it that goes late into the night. We prefer calm and quiet after about 10!
Our experience at the BWI concierge was just OK - nothing out of the ordinary. We had a disappointing room stay (loud banging noises at 2 a.m. two nights in a row -apparently coming from the adjoining restaurants) and we actually requested to be moved over to the GF.
So a lot depends on your previous experience but my money - especially with kids - would be the GF! Good luck!