Stability: Dr Android ROM is based on the stock rom that comes with your phone so you can be sure that it just works. It will not alter the appearance or the internals in any dangerous way. So if your device comes with Sense, Touchwiz or pure Android, that's what you'll get.
Optimization: There is always room for improvement. Dr Android ROM surgically removes any "fat" that will decrease your phone’s performance. Simple tweaks that don't mess with your device's stability are added.
More Room for Apps: There are always better apps available in the market than the preinstalled ones. Dr Android ROM removes those apps and lets you choose what you want to install.
Add-ons: Some missing things have been added to the ROM such as SMS application supporting 160 characters for some languages and worldwide Google Navigation*.
*Official Google Navigation is available only in the US. This is a modded version with no warranty by Google.