I've rarely seen blocking this bad--it's almost like the annual Party Congress is in town. Google.com is very sporadic as to viability, and often winks out. I've been getting around it (if off VPN) by using google.co.jp and google.co.uk which are somewhat more useable, but not 100% either.

I don't use gmail but a friend of mine visiting from USA for awhile does heavily. She's ended up having all gmail auto-redirected to a completely different for-pay specialty email site that does not get blocked. Which she can manage for a few weeks.

ETA: Whoops, it's October! The Party Congress is coming to town in about a week. So we can assume we are in one of our annual "lockdown" periods and particularly if your ISP is serving the Beijing area. The only question is whether it will be lifted come November.