My daughter attended GUG Mountbatten since 18 months. She's been with them for a year. I withdrew her in Jan'13 because she's getting bored with the class. The teachers are good and her name is Teacher Ivy. Couldn't remember her Chinese teacher name as she joined in Jan'13.
We attended the trial lesson in United Square and thought well of the teachers and curriculum. We only enrolled in Mountbatten because we felt that United Square is too busy and parking is a nightmare during weekends.
I am considering enrolling my younger daughter when she's 18 months.
Hope this helps.