Opinons please. I'm on the fence.
As a general rule, my advice is to wait for the first major patch for any mainstream major game. i usually take my own advice. I also like to wait until cheat codes become available so that when bugs crop up (and they always do) I will have a means to get around them. It also helps because I know of no major game that is play-balanced out of the gate (and sometimes not for a long time) and I don't want my experienced ruined.
Having said all that, I broke my own rules and preordered the game. I'm not sorry I did.
Of course, I have the experience of playing all of the single-player non-DOS FO games as well as Oblivion; and I'm familiar with MODs, data files and the Console, so I have a leg up. I'm also well familiar with the Vault Wiki and these forums, so I know where to go for help. I also have the confidence gained from experience (that obviously many new here lack) that both Bethesda and Obsidian are religious in patching.
And for allof you complaining about Steam, you should just thank any gods you may pray to that it wasn't Microsoft Games for Windows Live! (shudder...)
I was not surprised to find bugs and game breaking crashes and driver incompatibilities—although disappointed, since the engine is so old.
All-in-all I would unhesitatingly recommend that PC users buy the game.