The answer to this question depends entirely on what you expect to accomplish with a sterilizer and how much money you are willing to spend.
GOOD uv sterilizers will provide you with cleaner, clearer water.
They are expensive.
We run a 50 watt Emperor Aquatics sterilizer from BRS on our 300 gallon. We have absolutely noticed an improvement in water quality.
Having said that, a sterilizer does not eliminate the need for good aquarium maintenance like routine water changes.
UV will also not eliminate disease from your system. If you're hoping to eradicate something like ICH, save your money.
At the end of the day, UV is a tool for aquarium keepers; some of us like them and some of us don't. It all depends on what you want to accomplish and what you are willing to spend.