Due to an extreme pack of options, I have used Clinique Brow Shaper in Shaping Charcoaled for a very long time. This product is one of the few lines that carried a mid-toned cool ashy brown without any red or gold. The white lab coats always agree that Charcoaled is more flattering than Taupe (warm and red) or Soft Brown (warm and orangish) or Wheat (yellow).
Last winter I stumbled upon Anastasia Tinted Brow Gel ($21), and I immediately went for Granite, a very cool taupe that didn't scream brown at me. I tested it and Granite matched the hairs perfectly.
The only downside is when using a fresh tube, I find the product to be quite wet, and a bit too much comes out on the brush, so I have to work slowly and carefully or I can get clumps. I like this product best when I've used it for a while and the innards are just starting to dry out ever so slightly. Of course, it's like your favorite pair of jeans. By the time you get it where you want it, it's past its prime.
Another thing to note is this gel does not fill in brows. If your brows are not sparse and all you want to do is tame unruly hairs or give your brows shape, it's likely you'll find a good match in this line. My brows have lost a little volume, so I need both pencil or powder and the gel.
Bottom line: So far, Anastasia is the best gel out there to match my brow hairs and overall coloring. YMMV.