I'm not sure on the Redline, but I always hear good things about the Redline stuff. Personally, I change mine to the Royal Purple Syncromax about 6 weeks ago. I do notice a better feel in the shifter, it's less clicky or notchy, just smoother in general. I have not driven it yet though with cooler temps (below 70), and that's where my original fluid was very clunky until everything warmed up.
I don't think you can go wrong with either product, but like I said, I only have experience with R.P.