Which NAS to choose from?

Hi, I am looking for a good NAS to store my photos and music that totals to 8TB already and increasing. I am currently looking between the Asustor AS6404T and the Synology DS420. Since it is my very first time to purchase and eventually own a NAS, I am confused which would be the best NAS to purchase. I find the Synology more expensive and memory is expandable up to 6gb. As for the Asustor AS6404 is cheaper and memory is expandable or it already comes with an 8gb memory. Since this is my first time to purchase a NAS, I would prefer the one with more flexibility in terms of usage and memory that I find on the Asustor. I also do not have any idea which is better between Synology or Asustor. Thank you very much for your time. I hope I asked the right questions.

Yes, Asustor does compete with a hardware price. If you plan on using it for mainly third-party apps such as Plex then Asustor will be a better value for money. But if you need simple and reliable software to backup up your devices and organize your multimedia then Synology will do a much better job. You will also get more often updated software and new functions. Synology only limits RAM officially, but most people go for unofficial upgrades.I hope this helps.