Yes, there are some limits to a locked bootloader but it branches off from there. You are talking different themes, different iterations of blur (some keeping it while others get rid of most of it), and different tweaks. I think ROM's are one of those experiences that you have to try for yourself. There are certain features that you will want that another won't care about. I love Liberty ROM but there were a few things that had to do with car dock that really bugged me. It's really small, but you can afford to be picky when there are so many ROMs out there.

Check out the list in the sticky at the top of this forum.

 

Many roms make improvement behind the scenes. Most remove bloatware and improve memory cache settings.
Also many roms have custom settings panels to tweak different gui features and settings.

 

Seriously man, it's frustrating to me when people say just to try it, but it really boils down to the little things that make the difference between the ROMs. I mean, the Froyo Liberty ROM had a dialer that included a blacklist feature that I loved because I have a lot of people calling right now who want money that I don't have. There are many other "small" things like that that make a difference. On Apex, the dialer handled being in horizontal mode so that it looked better in my car dock. Not a big deal for some, but it was a point of decision for me.

It also seems that one person will say that a ROM absolutely sucks on their phone (FC's and such) while another says that they have absolutely no problems and LOVE it. So I go try the ROM and say, "I don't see the big deal."

Themes can pretty much be ported from one ROM to another and you can make one look just like the other. Just as TOM said, a lot is under the hood or more than meets the eyes (transformers!). Make sense?

 

where's my money fo0!