I think Twin Snakes deserves its bad reputation. It's not a crummy remake but it's not as good as the original. One of the biggest downsides is its redone script, which doesn't flow as well as the original. (There's a good article about it
here.) The music is too jammin' and doesn't have the ambient quality that makes the original so rich. The new cutscenes are fun, but they're
too over-the-top even by MGS standards. First-person shooting totally breaks the original game design, especially the Ocelot fight. I feel like preference for the graphics is the most subjective matter; personally, I like the grittier look of the original, blocky textures and all.
There's a reason MGS4 uses screenshots from the PSX version during the flashbacks, because that's Kojima's original vision and clearly the one he prefers. Twin Snakes is a fascinating retelling of the story but it doesn't hold a candle to the original, IMO.
There's rumor that Bluepoint, the studio who remade Shadow of the Colossus, is working on a remake of MGS. I think that'll hold a lot more promise because it'll be more true to the original experience, judging by how closely SOTC resembles the original just with some optional control tweaks but with greatly enhanced graphics. My biggest worry is whether they'd use the PSX voice acting, Twin Snakes', or completely re-record everything. I hope they use the original dialogue and voice recordings, assuming it's been preserved in high quality. Otherwise, the thought of a third MGS translation is, uh, interesting. It wouldn't feel right if they didn't get the original cast back—again,
for a third time.