My answer would be no, yes, and yes.
I have the Steeda dual-hook quad, firewall adjuster, and the stock cable. I had the Steeda cable for over a year too, but it is no good compared to the stocker. Pedal feel is much better (smoother and lighter) with the stock cable.
The greatest factor in how hard the clutch pedal is to press in is the friction in the cable itself. Mine has been smooth and light since I put the stock cable in. Before I installed it, I lubed it with white lithium spray grease. When I first installed it after I had been using the Steeda cable, I was amazed at how light and smooth if felt.
People have complained about the original Steeda firewall adjuster creeping out of adjustment over time, but I have never experienced this. I set it where I like it, and there it stays. I have seen people on Corral complain about having to adjust their cable every three months, but I am not really sure what the complaint is about. I have my hood open all the time anyway; if the clutch is out of adjustment (and for me, it never has been, once set), it takes ten seconds to fix it. It's not like you have to crawl around on your back like I did with my 72 Beetle.
For what it is worth, the new Steeda adjusters have a little allen set-screw to prevent it from backing off. I personally would not use that set-screw.
I would highly recommend the Steeda quad and adjuster. The cable... go with Ford. You can get the stock ones for about $40 online if you look around (if your existing stock one is no good). I got mine in a kit with a new clutch fork from Diversified Products Marketing. They shipped quickly, and I am pleased with their service.
Frank