Hey guys. I was going to buy Red Dead Redemption yesterday. But every store i went to was sold out. Sold out for the 360 version, they had almost every ps3 copy. I didn't bought it because i wanted the 360 version even though the differences are minor but i wanted the best version since i own both systems.
Then i remembered that the same time occured with FFXIII but in reverse. All ps3 copies sold but no 360.
So here's my question. I think a lot of gamers have both systems or will have them both in the future. They research and get the best version. So why spend time and money on multiplatforming the game when you can't get them identical? Do they earn the money they have to spend on the second version, I don't think so? So why do they even bother?

In short it's because few gamers actually have both systems.
The longer version is that the investment made in creating a multiplatform release is lower than its associated return on investment and as such, coupled with the fact that not everyone has one of each console it is more sound to do that. Also, releasing on just a platform could be seen (and truly is) as exclusivity which in general is made possible by financial agreements between the developer and the console manufacturer; in your case those advantages would be null.
Your true problem should be with the shop that doesn't stock appropriately and not with the devs.

Well games like FFXIII, the PS3 is undoubtedly the better one. The 360 had multiple discs, which is absurd for an RPG.
For games like Red Dead Redemption, that's not a big problem. People will buy where the people play, or whatever system they own. I almost always buy my console games on PS3 because I don't want to pay Microsoft money to play online, but sometimes with a game like Halo, Gears of War, MW2, that's where the people are. And there's the people who seem convinced the 360 looks a hair better than the PS3 so they just have to get that one (hint: NOBODY FUCKING CARES).
Whether you're porting or simultaneously developing on multiple systems, there will be tradeoffs. Maybe the PS3 version has nicer foliage but the 360 version has better textures, I don't know. Basically, it comes down to money. You're make a lot more selling on two systems than one. And frankly, that's fine by me as long as the game kicks ass.

I don't have a problem with it. I was just asking why they even bother making two versions because i thought the lost money on the "bad version". But you answered that question. I just buy the best version because i have the choice. If i wouldn't have the choice i wouldn't care (except for games that are so totally messed up on an other system like bayonetta)

Well developmentally, the differences between the 360 and PS3 versions are negligible. The overwhelming majority of the coding is identical, all the art, the ai, the sound and even controls are identical (they might look the same but both controllers have the same sticks & buttons). When you get right down to it the differenvce between versions is making the environment that the game code runs in and that'd be MAYBE 10% of the product. 10% more work for the possibility of up to 200% of the sales and it becomes mad NOT to.
Boy are you going to be shafted next week when sony announce their "premium" PSN which is rumoured to be the same as live gold

Well at least multiplayer will still be free. I find PSN+ more enticing than Live Gold, because I know if I don't want to pay for it I can still trash talk online.

I've played through Bayonetta on PS3, and a friend have played through it twice on two different PS3s (this guy actually doesn't even own a PS3), and neither of us had any problems with that version. No bugs, maybe a few pratically unnoticable framerate drops. Haven't tried the 360 version, so I can't really compare, but to say that it was completely messed up would be wrong.

Well I tried the 360 demo of bayonetta and I found it opretty messed up. Didn't seem to be a technical issue but more of a "what the fuck were they thinking making this shit and who thought this music was good????"

I thought it was pretty awesome, but a bit reptetive at times. My friend loved the soundtrack, and was rather annoyed when he couldn't find anywhere to get it.