I run a bare bottom on my 120 sps set up. There are pros and cons to the set up. I have a lot of flow in my tank and it keeps the majority of the detritus suspended so my skimmer can pull it out. That said, there are some dead spots where detritus builds up and thankfully, they are very easy to vacuum out and keeping this tank clean is very very easy. I also run a 55 gallon fuge with a lot of chaeto in it and I use filter socks to catch any addtional waste before it can collect in the fuge (wash the socks every other day and it's amazing how much waste they collect in a such a short time). Nutrient lvls in my tank are basically 0. The only pest algae I have is the calcerous types (halimida and a few others).
IMO, the only real con is the look of the tank. I think a nice shallow sand bed looks a lot nicer but as the tank matures and the bottom is covered in coraline it looks better.