So very simply...buy the best you can afford. There are some good ones including vortex and Nikon that are reasonable in price that function well.

Anyone who says that Swarovski or Leica are not better than the rest either don’t own a pair or just can’t afford it. There is a huge difference.

One warning is that Zeis Terra has major QC problems so it is a crap shoot on whether or not you get a good one.