I just recently started looking into DACs. Everyone and everything I've read tells me that newer is better. Technology is cheaper, what used to cost $1000 a few years ago is bettered by $300 today and so on. Take all that with a grain of salt IMO.
A local dealer had a Theta Cobalt 307 DAC (precursor to Chroma) that he took on a trade for a Naim HDX. I took it home and tried it out, not expecting much. My dealer knew nothing about it other than the previous owner used it with a mega-changer CDP and he was the only owner.
I connected to to my Rega Apollo, which IMO and a lot of other's opinions is the definitive $1k CDP. Compared to the Apollo's analog outs, its surprisingly better in most ways. Its more detailed, cleaner sounding, and soundstage and imaging are a good deal better. All the audiophile stuff. But it lacks that very last bit of grooving the Apollo has to my ears. Very, very little bit - not even 1% IMO. Everyone's idea of musicallity is different and very subjective.
I say this because a 10-15 year old DAC should not be able to compete with a current $1k giant killer CDP in any way, yet in all but one way it beats it. I've heard a few new DACs. The only one I'd take over mine is the Bryston BDA-1. Researching the BDA-1, I read that they said they were very surprised on how little the chip contributed to the final sound. They said power supply, output devices, and things like that made far more difference. Makes sense to me.
I think the main advantage of the newer DACs is their ability to reduce jitter. Transports have less effect on the music, I believe. Newer ones also usually have more inputs, USB, and some other features.
My experience told my not to believe the hype. Newer doesn't mean better, so long as the DAC was designed properly and they paid attention to everything and not just the chip.
Also, I'd drop Adcom from your list. Every Adcom source I've heard was sub-par. Their pre-amps and amps are decent, but their CDPs were awful to my ears. I haven't heard their DAC, but from their CDPs, I wouldn't give it a chance.