It depends on your needs and your budget.
The Maximus VII Hero is an extremely solid board for all gaming and overclocking purposes as long as you don't need more than 2 graphics cards and 4 sticks of RAM. It also has a LGA1150 Socket for Haswell, Haswell-R and the upcoming Broadwell CPUs.
The Rampage IV has a LGA2011 Socket so it requires one of the more expensive Intel CPUs (or a LGA2011 Xeon) and it's not compatible with Haswell-E. It allows for 4 graphics cards and 8 sticks of RAM. It's prohibitively expensive though. It's mainly for extremely high performance systems and workstations.
If you just want a high performance gaming system go with the Maximus VII Hero. If you're swimming in money or have specific productivity needs...