Fallout 3 was Bethesda's attempt at making a Fallout game by grabbing many of the things they found in the first two and smooshing them and rearranging them for the Capital Wasteland. New Vegas was made by Obsidian which actually include some of the original creators of the series, so they actually managed to blend new stories(Mr. House, Caesar's Legion) with the old(NCR, Brotherhood). There used to be a lot of bugs in New Vegas, but of course you can blame this on Bethesda since Obsidian was using their engine. The map was far more believable then the CW's theme park arrangement.
If you think the Courier's story is all about revenge then you've only been playing him/her one way. Someone pointed this out a while ago(probably Colonel Martyr) and it makes sense. The reason why the Courier feels the need to go after Benny is because he is a Courier who was payed a lot of caps to deliver a package to a very powerful and rich man. This man, if he doesn't get the package, will assume that something bad has happened to it and thus send out mercenaries to retrieve it by whatever means they can. This puts the Courier's life directly at risk, so s/he thinks that the best possible way to stay alive and avoid the wrath of a man like Mr. House would be to get the chip back and deliver it to him. This is just one of many ways to look at why the Courier goes after Benny, the reason you choose depends entirely on the character you make.