Sand bed or Mechanical filtration?

[Pro Fish Keeper]

Im about to start a 90 g reef tank. I was debating using a Fuval 304, undergravel filter and power heads. I was told the sand bed,live rock powerheads were a better way off cleaning your tank. Eventuly I would use a protien and uv as well in combonation with live rock, sand bed and power heads. They said you would have a more natural look and better filtration. I like the sand better and I would have plenty of lighting. Two Actinics(VHO) 2-4 55w power compacts for a total of 310-420 w. Which is better sand or mechanical filtraion?