I switched from Shield to ATV when one of the system upgrades half-broke Plex for months.
ATV is beautiful and foolproof, also much better at connecting to various Bluetooth accessories, but so limited software-wise (compared to sideloading non-TV optimized apps on Android TV).
I totally agree.
The site OP linked to at least warns about scammy sites and risks associated. It also tracks prices on official resellers.
I wouldn't use it to save a few bucks on an indie title, but it's a nice resource when waiting for a AAA game to become affordable.