I haven't been able to find it locally, but I would buy it if I found it.
I have full faith in Pennzoil products, and I'd rather give them my business than Valvoline or Castrol. Just a personal preference.
Although I've had Supertech ATF+4 in for the past 10k, and I've noticed just slightly notchier shifts when cold compared to the Red Line C+ that was in there.
All ATF+4s are high quality by default, so you can't go wrong really.
All of the licensed ATF+4 products should be nearly identical, so I would just make your choice based on price.
Redline C+ is not a licensed ATF+4 product, but Pennzoil, Supertech, Coastal, Valvoline, Castrol, etc are.
The problem is that not everyone wants to change their ATF twice as often. I would also think that a groupV base oil would outperform a groupIII.
Pepboys around here stocks the full range of Pennzoil ATF products.
I had good results changing out my factory fill Mopar ATF+4 and replacing it with Redline C+. Interestingly, Pennzoil's website doesn't list their ATF+4 as synthetic, whereas other +4's do, like Mopar, Valvoline, Castrol etc...
Pennzoil makes good products, and I'm sure their ATF +4 follows suit.