I want to execute a search that matchs documents within an date range. Now i have two ways to accomplish it, and the one is to use DateFilte, the other is to use RangeQuery. My question is which one is more effective?

If you are going to use the same DateRange over and over, create a filter and cache it for reuse. If you have varying date ranges, it might be easiest to use Range Queries, although using them on simple Date fields will cause problems.