IbproArcade is better, by FAR. It has much more games and is more efficient on the server. The only negative is the fact that it is not a native vbulletin script. But why should I have to download VBarcade and spend hours modding it just for it to have some of the functions that Ibproarcade has out of the box? You have to nitpick small details to find things on vBarcade that are better.
If I was already using vBarcade and was satisfied with it and its games, I probably wouldn't switch...but if I was looking to install an arcade for the first time, go with ibproarcade!