S3 after the Jellybean Update

Hey, I'm new to this forum, and Android in general.

I got my S3 in early December and started using it earlier this month, switching from Blackberry. In India, the OTA update for Jellybean just came out and I went ahead and updated it.

Since updating, I feel like my battery life has gotten worse, and it seems to drain out faster. Currently battery stats are-

90% after 1h 28m on battery with screen use 40%

Also, I've noticed a slight lag, particularly when I open my contacts or phone to dial someone. It takes about 3-5 seconds to load the contacts.

Google Now is disabled, just in case anyone was going to suggest that. I've read that I should do a factory reset?

Anyone else facing this issue? Any fix?