I bought a 512GB LCD on release and barely used it, maybe 50h at most. I just found the fan to be really annoying. Once the OLED was announced and reviewers mentioned it was much quieter, I bought it on a whim and sold my old Deck to a friend for cheap.
The fan noise is massively improved, I pretty much don't hear it ever. I'm actually using the Deck now, probably already more than I ever did old Deck, and will look at the performance for games on it, before I buy something.
So, even though I've had a Deck since launch, I'm still pretty new to it, and can't say too many other things about the differences. It was still worth it for me.
Maybe, back then I read that there are two fan models going around and one is better than the other, so who knows. Or how putting a bit of pressure on a certain spot could help, or things like that. I was toying with the idea of ordering a replacement, when the iFixit stuff was announced, but never did it and forgot about it.
So far my friend is mostly emulating older handhelds, so it doesn't get too hot in the first place, and even if it gets louder it doesn't seem to bother him for now.