Recommended contractors in Bay Area?

Hello,

I'm looking to refinish/resurface my swimming pool in the Bay Area (specifically in San Jose).

Can you recommend contractors who you've had good experience working with? I'd also like to hear contractors I should stay away from. What payment schedule did you use with these contractors and for what purpose? How much did it cost you to refinish/resurface?

I noticed in another thread that somebody said $5K for replastering with only 5 year warranty is not the best. What type of warranty should I expect to get for either plaster or fiberglass from contractors?

Also, I noticed somebody posting asking about experience with UltraGuard (http://www.poolrestoration.com/index.htm). Anybody out there has used UltraGuard and can share their experience?

Thank you for any advice and help.