I had a Marantz SA 8005 and I upgraded to a KI Ruby. Interesting comments about the high frequencies of the 8005 - that was not my experience. The frequency response was very flat as far as I could tell. I compared the 8005 directly with my PSA PerfectWave MK II DAC and they sounded very similar. I would easily recommend the 8005. It is built well and will last many years.
The one caution I would give you is to make sure that whatever SACD player or transport you buy uses a brand-name transport. Marantz makes its own transports so you are safe with them and since Denon is owned by the same company their transports will be good quality as well. Two other well known transport manufacturers are TEAC and Phillips. The Phillips transports are no longer in production but you can find players with them on the used market (some of the top end transport makers still use them from new old stock). I would avoid any transport manufacturer that doesn't specify exactly where they get their drive units. There are several companies that use cheap computer grade drives that fail quickly.