Originally Posted by R_Dub
One big plus about the GSA is the pointer knobs! i cant stress enough how nice it is to "feel" where the knob is rather than having to look down to know if you've returned it to center. Other than the cost, i dont know why Jerome wouldn't put pointer knobs on his ISO (and mixer!).
If i was in the market for a 19" ISO, i'd pick the GSA over the E&S for that reason alone.
If your preference is for a particular style of knob you could just ask them to ship without knobs and request to reduce the cost by $10, you can then buy whatever you want and put them on yourself, easy.