Being that the AVS is an FPGA solution, it has potential to add additional features and be continually updated. For $185 it provides great features, 100% compatibility with Everdrive/Powerpak/NES/Homebrew games, and value to retro enthusiasts -- in my opinion, much more so than the RGB mod and framemeister.
The NES-RGB solution loses some fidelity converting from analog to digital and requires expensive add-on hardware like the Framemeister to provide comparable high definition fidelity. It's definitely playing second chair to both the Hi-def NES and AVS, for me. (MUCH more expensive, less visual fidelity, no future updates outside of framemeister profiles). I have both an AVS and a Hi-def NES kit on order.
Hi-def NES and AVS both do not have any inherent lag introduced with the high def digital video output. --And both are compatible with Everdrive and all other NES games.