Do you recommend retail DVD version or Steam version of the game? Which is better for updates, DLC's , glitches, bugs etc?

There is no difference except that the DVD version includes some of the download on the disc. Both use Steam and will require that you download ~20 GBs.

Personally, I would just get the digital version, then you don't have to wait for the mail or drive to a retail store. Hopefully you have decent Internet speeds, and no Internet quota.

Thanks. This helped a lot, I didn't know after buying retail we have to download 20 GB more from Steam (right?) +emailing..ohhh:(

Yes I have some internet quota

The Install is over 25GB and a DVD can only hold 4.7GB (single layer) so do the math . With Steam you don't have to download it all at once (one session), but you cannot play the game until all of it is downloaded.

Does the DVD version contain a poster and/or a manual?

AFAIK, it has a paper slip with the Steam code and a DVD with some Fallout 4 data, but don't quote me on that.

Mine contains a survival guide (though only two pages) and a poster with all the perks.

If I'm not mistaken the steam code is located at the back (last page) of the survival guide.

Also the DVD should contain ~5.2GB of data.

Yes it comes with the perks poster. No manual. If you want, you can backup the whole fallout4 steam folder into a bluray disc. I m still old school where I like physical disc.