Prefab granite vs. granite slab

   I'm installing granite countertops in my kitchen. Received 3 bids. One is $1,000 lower. Reason for lower price is prefab granite vs. granite slab. Research online I have found both pros & cons. Major con with prefab is the install is much more room for error, requires a more simple install project, granite itself can be thinner. Need help with decision. Want to save but not regret!!!