I read that Red Sable brushes are not as good with Acrylic paint as they are with Oils. Also I read that if you use Red Sable with with Oils you should not use the same brush with Acrylics. The article also said Synthetic brushes were the best for Acrylics. What is your opinion.

Bob,

I've used Red Sable for both oils and acrylics and never had any issues. However, before switching between, I thoroughly clean them.
Same goes with the synthetic brushes.

Steve

I use red sable as well as synthetic brushes, for oil's, enamels and acryllics. Never had any issues.
Just make sure you clean them well. If you clean a brush in white spirit and shortly there after use the brush with acryllics, you might get a problem. Make sure any cleaning fluid is completely evaporated.

I do prefer god quality sable brushes over the synthetic ones. They keep their shape a lot longer.