Without you telling us the tone or sound you are going for, it is hard to suggest what would be best for you.
The Beta is a great pedal if you are looking for a nice Soul/bassy sound (Ampeg B-15 comes into mind), but the bass boost might be a problem for your Streamliner as the amp is on the darker side of things.
I personally went for a COG Knightfall after Tom suggested it for my custom build "The Octabass".
The Knightfall is a versatile drive that can go from nice and clean with an edge to distorstion.
I cannot coment on the Darkglass as I only own the B3K and I have never been interested in the Aguilar.
The are a gazillion drives in the market, which is a good and a bad thing at the same time...
Good luck mate!