How will phone manufacturers differentiate their products?

[TWO515TY]

Sorry if this has been posted somewhere. I looked through the 4 pages and didn't see a similar topic.

My understanding is that Microsoft is launching WP7 with only Chassis 1 phones available. Now with the exception of keyboard vs no keyboard options, how are phones with similar designs going to be considered different from one another?

For example, let's say HTC makes an all touch screen phone and LG and/or Samsung also make an all touch screen phone. How many major differences can there be between the 2 or 3 phones, if OEM's are not allowed to customize the software with their fancy (or not so fancy depending on your opinion) UI's and extra software features? Won't we all end up with slightly different looking phones that are running the exact same software?

I hope I'm not being too general, but so far, I don't see any reason (except for preference of a keyboard) to pick one WP7 device over another, because it seems like they will all offer the same experience.