Though it might not be an issue in your neck of the woods, the ABS pads have a reputation for warping in situations where they're exposed to a lot of sunshine/heat. That's merely what I've read; I've never used one. I do know they don't fit as well, and as mentioned by challenger6pak the lower plastics around the cluster nacelle are contoured differently and will not match the 1970 pad. Not only are the '70 trim pieces one-year-only, they're Challenger-only so they tend to be more expensive than the "every other E-body" versions. If you can live with the mismatch, so be it. If you can't, replacing expensive trim to match a less-than-ideal pad isn't particularly cost-effective in the long run.
I researched and agonized over dash pads for more than a year. I have a great original AC pad, but my car had 3 dash speakers and the good one is single-speaker. I saw complaints about virtually every vendor except the one I used, some of whom do not remove all the original material (Just Dashes), and saw quite a few about the ABS cores. The clincher was my best friend looking at
ABC Moparts' samples at Carlisle. He called me, still standing at their site, and said, "He's got Year One's old tooling." Both of us had worked at Year One and know those pads were made using the original vendor's molds
¹. When Year One was doing them, they were widely considered the best in the industry. I called Bob and he verified the pad gets completely stripped and re-foamed/covered as original, using the original process.
Sold! Bob at ABC restored my demolished original pad. Close comparison to both of my original pads (I have another 3-speaker AC pad) showed it's virtually identical to the originals. It has the same flaws in literally the same places; the pads were never perfect when new. The only real difference is "YEAR OИE" (the N is backwards
²) stamped in the VIN recess, which conveniently gets covered by the VIN tag itself. As a bonus, ABC Moparts' service is significantly
less expensive than the others--only a couple hundred more than an ABS reproduction.
Bob didn't have any 3-speaker/AC cores, so I had to send him mine to restore. All of the restorers have a core charge, so the real only downside was the wait. It was well worth it. I can't recommend ABC Moparts highly enough.
¹ ABC Moparts likely can't advertise "from original molds" since they bought them from Year One, who'd modified them slightly with their logo. Year One did advertise them as such in the 1990s.
² "Year One" is a trademarked name so ABC can't use itl, hence the reversed "N" in the stamped area.