Ultimate Bet allows late tourny registration up to third blind esclation in most cases, which they call "open for alternates." It continues to boost the prize pool and the number of in-the-money finishers. You also avoid all the donks going all-in the first few hands. The one tourny I registered late I finished 4th, so I like it.
Before entering, you should view the current leaders and see if anyone is way, way out in front (i.e. like 10x the starting stack). If leaders only have 2x or 3x the starting stack, it's still worth it.