I recently went to BI, and it's awesome. I do miss the custom battles, but all it takes is switching out the disks and 3 taps of the backspace button, and I can do it all I want (but I'll try Sheep's link in a minute). I think shieldwall and warcry are two awesome benefits, and the naval invasions aren't overpowering (I usually see halfstacks landing in various places, like Carthage to Sardinia and Maks to Krete).

The conversion is simple. After installing EB, go to the EB shortcut. Right click and go to properties. Where the target says "RomeTW.exe", add "-BI" to it, so it looks like this "RomeTW-BI.exe". That's it. Then you just double click n' go.