I would go with the G2 here. But there is an alternative you can find down the page.
The relative merits of the processors here are not so important. Its the fact that the G2 has a vanilla Android interface, which makes it look simpler and less of an iPhone wannabe. It also comes with Android 2.2 from the start instead of Android 2.1, and would upgrade sooner to Android 2.3 before the Vibrant. Being able to upgrade to the latest Android OS can be quite important due to the features and speed the latest OS has.
I got a Desire Z, which is like the G2 but also has Android with a full HTC Sense UI. I also owned a Samsung Galaxy S i9000, which is the generic international version of the Galaxy S, the Vibrant being a carrier branded version. Despite the faster processor, larger touch screen and more brilliant colors of the Galaxy S, I'm much happier using the Desire Z. It just seems more stable and less buggy.
Also when it comes to updates the HTC does it the true Google way which is to push the entire update right into your phone without need to sync it to a PC. With the Samsung, you need to do it with a PC and software called Kies Mini.
You have an alternative, which you can find in Best Buy. Its called the Samsung Google Nexus S. Basically its a Galaxy S variant that's loaded with the latest pure Android with updates straight from Google itself. If you want the latest Android updates, this is the phone to get. This is the phone that combines the advantages of the G2 with the advantages of the Vibrant. Being the Nexus, this is what you call the official Google phone, or Google's flagship. If you're trying to choose between the G2 and the Vibrant, the Nexus S has to be mentioned. With the three, I would go Nexus S, then the G2 then the Vibrant.
