Usually, this type of a question on this forum will invite subjective recommendations. Nothing like auditioning both these amps - take your time with these two choices as you seem to have narrowed down, cutting out the noise. The reason I'm saying this is because of my personal experience here and with other forums.
A few years ago, when I wanted to switch from my home theater to pure stereo, I was in a similar dilemma. In fact, I had the same question - Marantz PM5005 or CA AM10. After getting some 'private message' advice and looking at the reviews across this and many other forums, I took the plunge and bought the Marantz PM5005 (from HiFiMart). I was happy with the purchase - but always felt that there was something missing with the sound; something that I couldn't put a finger on. I also changed quite a number of speakers to get the sound signature I desired. I went to Volumate (in Chennai) to audition the PM6006, thinking that I made a mistake going with the PM5005 instead of the hyper-reviewed 6006. I auditioned for nearly an hour and a half to the same songs and source that I usually listen to and was happy with the decision to go with PM5005 - can't find a day and night difference in sound/sound signature between the 5005 and 6006.
After nearly 2 years of living with the Marantz, I sold the amp and the speakers (Monitor Audio Bronze BR2) and decided to wait before taking the plunge again. This time, I went back to one of the lesser-known dealers in Chennai and auditioned the Cambridge Audio SR10. The audition included pairing them with several bookshelves and towers, including the Elac Debut B5 and the Tannoy towers (can't recollect the model name). IMPRESSIVE sound. Just the right dose of mids, bass and treble that I have been missing from the Marantz. In other words - the SR10 brought a lot of character and the punch, with 'zero' adjustments to the bass and treble controls. And boy, to me this had a warm sound, compared to the Marantz. Bought the SR10 right there with a good discount, took it home and paired with JBL Control 1 - absolutely no bass, but the mid-range/vocal and instrument separation was top notch.
Luckily, I was able to buy a pair of GoldenEar AON3 bookshelf speakers from Mumbai. Now, I listen to songs for hours together without fatigue. One word - I'm super happy with the CA amp than I ever was with the Marantz. Maybe, just my ears. So, I'd suggest you audition. Nothing like it. That will keep you happy for years, unlike me having to learn it the hard way by buying a Marantz that my ears didn't like much.
The setup that's keeping my happy now: CA SR10 + GoldenEar AON3 + Schiit Modi 3 + Apple Music
All the best with whatever you decide to go with!