Reliability? I had an '09 Hemi and then a '19 Hemi. Between them, I put on 275,000 miles.
Between them, it was in the shop something like 7 or 8 times to have a cracked exhaust manifold or broken headers bolts fixed. After so many times of that on the '09, when I traded it for the '19, I thought "surely RAM has figured this out and fixed it by now."
At 42K miles, my 5th gen '19 needed the same repair. When I traded it at 73K miles (for an EcoDiesel), it had just started to sound like it needed the same repair again.
Hemi, reliable. LOL!!
Knock on wood, but I'm not too worried about my SST HO motor needing more trips to the shop than my Hemis did.
And power? Again, LOLOLOL!!! The Hemi is a dog. Gutless down low and not that strong on top.
The Hemi was great - when it was a new-ish, modern-ish design. But that was a LOONG time ago. And it hasn't been really updated since.