My 10u DD has the Boombah Beast bag for 2 years now. It has plenty of room and has stood up to the beating that she puts it though.
We tried the Boombah. My DD(16U) had to much stuff and busted out the seams a few games into the season. She has an easton now. I can't remember which one but it's the bigger one. DD loves it. Plenty of room for all her gear, extra gloves, bats, shoes, cell phone case. It even has an insulated pocket to keep a water bottle cold(She put a frozen water bottle in there to test it, and it was still partially frozen at the end of the day). Industrial grade wheels are a must.