My current favorite - Armaspec Fulcrum 45/90 Degree Short/Full Throw Ambidextrous Safety Selector

I've tried a number ambi selectors, from very cheap to reasonable, and of the six different ones I currently have this one is by far my current favorite. It toggles easily but still has a satisfying snap. The larger barrels on the ends make it easy to feel with winter gloves but stay out of the way barehanded. The only downside, which is tiny, was that the screws don't come with thread locker applied but that's easy to fix.