We've come a long way when it comes to obtaining the best video, and audio, quality for our beloved retro video game systems. Reverting back, there was one flaw which we couldn't help ignore: "jailbars." Without getting too technical, "jailbars" are known for its frail, yet annoying, video interference from the console's motherboard. The very first model of Nintendo's Famicom and Nintendo's model 2 Nintendo Entertainment System (NES), known in the video game circles as the "toploader," were known for having these awful "color stripes" that add unnecessary havoc to one's eyes in a high-pressured game play (especially scenes using the most gradients). Some folks out there are able to ignore it, no problem. Others refuse to have their consoles modded to preserve its natural state from whence it was marketed originally. While I'm one of those who preserve things the way they are/were, there are exceptions where it just has to be fixed. (I do have the NES toploader and is currently being modded. More talk on this when I receive it back.)
All due to respect to 'clone' consoles, which I've stopped being a fan of, getting the real hardware is the way to go. When one has learned of the idea behind avoiding the dreaded "jailbars," s/he learns about the AV Famicom. The "AV" refers to the console's feature in using composite video/audio cables, as opposed to the horrid coaxial connection. Because retro gamers fear the results of having to mod the NES toploader, they easily revert to this system instead. I don't blame them, as I own one myself, but with my usage, I'm happy to provide some things that this beautiful machine can't do. Yes I know, the AV Famicom can't help you pass your midterms/finals, help drive you to work, teleport, cure every human disease in existence and so on.
Without modding this particular model as well, it cannot output S-Video. While I have mentioned that the Super Nintendo can proudly output S-Video, the AV Famicom, being 8-bit, can't output anymore beyond composite. If you're one of those hoping it would, let alone output RGB/Component, having it modded will be the option for you.
Depending on the title(s) you play, some games output true stereo, but generally it can't. It only outputs dual mono (again, this is 8-bit we're talking here). My own friends think I'm on something whenever I tell them I love the classic 'chip-tune' music. That's the best thing ever, come on now! Anyway, while there are specific titles that can output stereo, in general, it doesn't.
The AV Famicom also cannot play regular US/EUR games. Those gray cartridges have a wider cartridge pin (72 pin) while the Famicom cartridges are lesser than those (60 pin). Therefore, no NES games can fit without a 72-to-60 pin convertor, available at most third-party online shops and popular auction sites. While the price of those convertors vary, the results aren't always clear among the retro community—some say it works and is a great choice if one grew tired of dealing with the "jailbars" that the NES toploader spews out, while some say it doesn't always work for them and suggest to invest in a more pricey convertor. This brings us to the fourth thing the AV Famicom can't do:
Play ALL NES games via the 72-to-60 pin convertor.