Yup, I knew it was 2020-something and as long as they update the cars properly, nobody will care as the mustang platform is very good, especially in the GT350 trim or PP. I love the Dodge stuff but I am done waiting and getting a 2019 Camaro SS 1LE very soon instead, not paying $50,000+ for a car I've already had from Dodge. They need to get off their butts and update the cars and not just fender flares or more power.
The Challenger is a good car, that said if you've already had one and want something new I could see wanting something else. Mustang platform is great a friend of mine had a GT350 that I had the pleasure of borrowing a few times and what an awesome car. The only thing I didn't like about it is that it would tramline going down the road like nothing else I'd ever driven. I would probably go with a Mustang GT PP with the 10 speed if I was to buy a new Mustang, good value and the recent reports of GT350 engines coming apart would have me a little nervous on them. I'm pretty cold on the Camaro but I hear the chassis dynamics are the best of the 3 so if that's what you're after and based on the vehicles you've mentioned it sounds like it is, it's probably the best choice at this point.