I'm with Cara here and my daughter will be attending the same kindergarten this year. My wife works in Kowloon Bay, close to Kwun Tong and travel time can be superbly quick unless traffic accidents. I personally work a lot in China and while I don't share the 35 minutes to Sheung Shui theory (can take almost that to get to Shatin some days) it's not a huge hassle - can also depend on where you cross the border - much easier in HK to select the right border crossing than try and get where you want Shenzhen side. Travelling to Tsim Sha Tsui / HK Island side for other locations in China by ferry isn't too difficult either once you know the quickest ways to go by public transport.