I want to preface this by saying that I have only played 3 games of the 360 demo, and 2 games of the PS3 demo, so my opinions are based on little playing time, and on the demo of course.
I played the MLB 2K9 demo for both systems (PS3 and 360). It requires that you use the R stick to pitch and bat in the demo. You will have the option to use buttons in the retail version. I don't normally use the R stick hitting, and I am not very good at it, so it makes it hard for me to judge the gameplay.
Graphics and Sound:
The graphics on the 360 version is slightly better due to less "jaggies". The framerate on both are very good this year in the demo. So really its a wash if you have both systems, it would depend on which controller you want to use and which system you prefer to buy for. If I buy the game it will be for the 360, since I am buying MLB 09 The Show for the PS3.
Player modeling is not as good as MLB the Show, but they look pretty good. The stadiums look great. There is a dynamic camera in the demo version that changes depending on where the ball is hit. I do like the camera overall, but players look pretty small when balls are hit to the outfield. This may be a good thing. Definitely for robbing HRs it is.
One thing that bothers me is the size of the ball target this year. It is much bigger, so it makes it hard to pinpoint exactly where you want to throw it. It has a bit of an arcadish look to it.
The commentary in the demo is excellent. I think the commentary in this game is better than MLB The Show. It flows real well, and Steve Phillips interacts well with Gary Thorne. He does babble on like he does in real life, lol. Its hard to judge how much commentary there is from a demo, but this was very good. The background sounds are pretty solid. Someone complained about the organ music, but it didn't seem to be noticable to me. I have only played a few games so far though.
Gameplay on demo:
This is really really hard for me to judge since I am not a swing stick R stick guy. But, I had a lot of fun with the demo. I was able to read the pitches well, and even took a walk once. Camera angles were set in the demo, but you should be able to change them to your preference on the retail version from what I have read.
One thing that really concerns me for the retail version is that the CPU batter swings at about everything in the strike zone it seems, even if it is on the "black". The CPU batter doesn't seem to work the count much. I have only played a few games, but the CPU only took one of my pitches in the strike zone. It did swing and miss alot, but did not take any except 1. This is a real concern if this is the only baseball game you will have this year (360 only owners).
Fielding: The fielding is pretty good overall, but sometimes the fielders are a little sluggish from the get go. You have to manually switch to the correct fielder at times. You get used to it, but after playing the ultra smooth fielding in the Show demo, you will notice a difference. It is not that bad though in my opinion (from the 3 games I played).
One Big Big change, is that if you don't get your pitch just right, you won't throw a meat ball pitch like last year all the time, but instead you will just miss out of the zone. There may be meat ball times if it is extreme, but I did not encounter this. This made pitching much much better. I find the pitching to be fun, but I am not sure if I would stick with the R stick since I am no longer the joystick jockey I used to be. I really could stick to it this year though since there is a reduction in meat balls thrown.
I have read that the run down "pickle" problem has not been corrected. That sucks. I did not encounter this, so I can't comment. It is not a game killer for me though. The CPU will steal on you if you don't pay attention. They were pretty agressive against me my first game before I started checking them at 1st.
I have also read there is a Franchise problem with the retail version, but that a patch (using Xport / Xplorer 360) will be out on day one.
I will post the patch using Xport/Xplorer 360 if I get a copy of it (whether I buy it, rent it, or get it from the library. So if you are one of those people out in the boonies or don't have Live, check my blog after the game releases. You will have to have a way to put it on your HDD like Xport.
Overall, I think if you only have a 360, and want to play baseball on it, this game seems pretty fun and looks very good. It is better than MLB 2K7 or 2K8 from what I have seen from the demo. Next year will be very very solid, if they fix some issues. If the CPU not working the count is a game killer for you, you may want to rent it to see how that is, or wait for a possible patch for this. This one potential problem may keep me from buying this title this year. I will have to check the forums and see what people are saying about this on the retail version.
I am really on the fence about this one. I have a $10 coupon from Newegg.com if I spend at least $50 so I am considering using this for this title. I bought 2K8, but only played it a few times last year. This was because if you missed your pitch using the R stick, it would throw a meatball. That doesn't happen this year.
Looks like we have 2 very solid baseball titles this year, but I prefer the gameplay of The Show. If you are one of those people that find the Show boring (and I can understand this gripe at times (it is very sim)), or you don't like batting/fielding/pitching in the Show, don't have a PS3 (what other reason is there to have one, lol
)you have a much better alternative this year. I think 2K9 with VC in control will really be a strong contender next year.