Macworld has benchmarked a BTO Mac mini with a 1 TB Fusion drive, 2.6GHz quad-core Core i7 processor and 16 GB of RAM. The extra RAM cost them a whopping $300. (Why has Apple RAM always been so expensive? Does it contain unicorn tears?)
The benchmarks are thorough, but I think this sums up how the Mac performs:
"The BTO Mac mini is $1449, but it adds up to one of the fastest Macs the Macworld Lab has ever tested."