I read Ricardo's love letter to my smartphone post and I can relate to almost everything he wrote. My problem is actually one of having two primary phones needing to share a single SIM. I love the HTC Radar 4G and Samsung Galaxy Nexus and have to decide on a daily basis which one gets the nod for the day. Sometimes I even switch back and forth during the day. They are both fantastic phones for T-Mobile and each has their strengths and weaknesses.
The primary reason I put my SIM into the Radar 4G is due to the simplicity and elegance of the Windows Phone OS. I find it extremely easy to get things done efficiently on Windows Phone and if I know I will mainly be using text messaging, making phone calls, listening to music, working out, or playing games then the Radar 4G is selected.
Both devices have decent cameras, also have room for improvement. I can perform nearly all the same functions on either device, but the tasks I listed are optimal on different platforms.
Keep in mind that I do also have a Verizon account with an iPhone 4S and usually have that device as a backup to my primary T-Mobile device. I use my iPhone for photo and video capturing, but the OS is getting stale and I personally prefer to use the Radar 4G or Galaxy Nexus with ICS instead.
As we celebrate Valentine's Day today, I wanted to let you know my SIM is in the Galaxy Nexus. Then again, my Radar 4G sits waiting in my bag too as my two loves battle for my smartphone heart.