Do you all really believe that these roms are much better than the stock froyo?
Seems to me that other than bloatware on verizon's phones, the rom works pretty well?
If you can enlighten me, please do so...i'm asking just because i want to know if changing rom is really all its cracked up to be, before I get myself addicted
Depends on what you're looking for.
Many custom ROMs have wifi/USB tethering built in, newer versions of the Google apps than are included with the stock HTC ROM, added/modified/changed features to tweak certain system settings (or expose hidden settings), ability to reskin buttons, the notification bar, highlight colors, lock screens, etc.
Some drop HTC's Sense for a generic Android look & feel while some keep the Sense look (or parts of it) and HTC custom apps (HTC's mail app and widgets, for example).
Custom kernels let you overclock the phone's processor or underclock/undervolt for better battery life, dynamic clock speed adjustments, etc.
There are so many options and combinations, it's hard to describe them all. Some people want control of each and every potential option of their phone while others are happy to have a vendor-supported ROM with well-documented features and stability.