We are WDW vets who have been going to DLR every summer for the last 6 years. We love the DLH. It is different from the WDW resorts and we really enjoy staying somewhere that is not practically a carbon copy of places we stay at WDW. To us, the GCH, while wonderful, is just a scaled down version of WL (which is similar to the feel of the AKL lodge minus the animals and with a smaller pool). We love WL and have stayed there several times, but we want something different at DLR, not just something that feels like a smaller version of a place we have stayed at WDW. DLH has so many Disney touches-- it just feels Disney (a little less since the front lobby remodel inside and out that removed some of the beautiful Disney touches and left it more cookie cutter regular standard hotel looking- but for someone who has never been, you won't miss what is no longer there!) As far as the pools, for kids the DLH is probably better. DLH has a great gift shop inside. We have always run into Goofy in the lobby at least once on every trip. As far as restaurants, DLH has some good options (and Goofy's Kitchen if you are looking for a buffet character meal), but at DLR any of the hotels are basically at DTD, so you have all the DTD restaurant options too. Plus, the resorts are so close together, you could easily walk to another one to eat. Allears.net has all the restaurant and menu listings for DLR just like it does for WDW. I don't recall the daily resort activities being as extensive as you find at the WDW resorts, but I do recall there being some. I know they do have movie nights out on the lawn like you find at WDW- although I don't know that they are every night like at WDW. The one thing that GCH has is that if you are getting a theme park view room it can't be beat-- by theme park room, it means that you look out the window onto the walking path inside California Adventure below you. You also have the benefit of the gate directly into California Adventure, but you don't want to use that gate at opening in the mornings because the lines are longer and distance wise it puts you behind the crowds going to the main attractions at rope drop. I have never been inside Paradise Pier, but our friends stayed there and they said being used to WDW resorts, it really just did not have that Disney feel to them. It felt more like a plain hotel than a Disney resort.
If your 6 year old is remotely still into Princesses or Cinderella, she will love the musical light up headboards at DLH!