Vortex is the most popular because they are in the hands of the most TV personalities that get paid to endorse them and they are the most profitable for the stores that sell them. Vortex would not make my top 10 list of good optics companies as they are a sourced glass from the orient and the orient definitely doesn't make the best glass, not even close.
If you want great bino's that you can see right up to dark, Meopta (made in the Czech Republic) and Swarovski are the best by leaps and bounds and are made differently as well. Meopta may be hard to find in stores because they haven't sold in the US for very long but they are an 85 year old company that actually imports German glass and raw metals to make their products. Their Optika series of 8X42 or 10X42 are the best glass for the money and are the ONLY bino for $350 that has magnesium frames and aluminum eye cups, all other are some form of plastic at that price point. My favorites because of their size and weight is there 8X25's. I've never ever seen a pair of 8X25's that were worth $1 before I came across these. You can see great through these because they use premium glass. Meopta also makes all the glass for the sighting systems in out Abrams Tanks and their is no way the USA would use inferior glass in those multi million dollar tanks.