Unreliable (eg. 10 bus never shows up or very late) and Caltrain is not reliable either. I've complained multiple times about the 10 bus not showing up or showing up 15 minutes late. I've learned how to walk off the airport property because of this issue. I use public transit to save money, but I always try to avoid using public transit when it involves SJC. Light rail is reliable, but VERY slow.
Agree, the shuttle is unreliable. I stopped using this route to get to SJC because of it.