Chrome bores are fine if plated properly and the cylinder walls don't peel. It is very unlikely that if the bore is not perfectly concentric and true during manufacture that you can ever break it in properly because the chrome is so hard. I consider it a cheap way to manufacture an engine as you do not have the large expense of making a liner and the corresponding port openings. The same with steel rings, they are hard and difficult to break in. In an ideal world a properly manufactured chrome bore and steel ring would not require any break-in at all. Additionally, should the chrome peel on a chromed bore you have only two choices, replace the entire crankcase and cylinder or dechrome and rechrome the bore.

Bill