First, I want to start this review off with a disclaimer. I got the opportunity to try out the Abraxas set because I did some work modifying a friend's guitar. The guitar the Abraxas set went into is a PRS SE Tremonti. I also swapped in a Core Nut, John Mann MannMade 2000NOS bridge, and locking tuners. The guitar is inherently dark (darker than I like). The new parts definitely made the guitar ring more and helped tuning, but the guitar is still pretty dark.
Now, with that out of the way, my thoughts on the Abraxas set. They have chrome covers, and it is a matched set. My friend did not opt for coil splitting but did want a phase switch. For the bridge pickup, it is quite neutral tonally, very balanced. Personally, for my tastes, the top end is too rounded. I prefer a pickup with more inherent top end sparkle/cut/sizzle. The neck pickup is actually not much darker than the bridge. It has the character of a neck pickup, but it isn't as dark of a pickup (relative to its position) as the Abraxas bridge. The Abraxas set is very responsive to tonal changes on the amp because the tone is so balanced. You can get sparkle from the Abraxas if you set the amp up right, but it doesn't have that character inherently (I scooped the mids a bit and boosted the highs on a Mesa Mark 5:25 to get it to sound nice clean). It does well with gain but does not handle gain as well as the other Bare Knuckles I have tried (Crawler, Holy Diver, and Juggernaut). For how hot the Abraxas bridge is (over 14k) it did not seem as hot as I was expecting it to be. It definitely does not drive an amp as hard as the Holy Diver or Crawler. I prefer bridge pickups with more character, so honestly it isn't really my thing. I can see why some would really like the Abraxas bridge, especially if you use your amp to do the heavy tonal lifting (I don't own the Mark 5, it belongs to my friend), which my friend does. He also wanted a guitar with a thick and throaty tone. The Abraxas set is definitely thick. It can sound throaty but isn't as inherently throaty as I was expecting given what I have read about it and the specs of it.