It worked fine when I turned it on, but it's essentially a paperweight now because the US mobile carriers have all upgraded to 5G, and this is a 3G phone.
The thing that struck me while doing this is just how tiny the Nexus One is. It's a full-featured (for the day) smartphone, but it's less than half the size of pretty much all the mainstream smart phones today. Battery life was decent, and the apps were pretty functional.
My current phone is about twice the length, 50% wider, and twice as heavy. Battery life has been getting progressively worse with background apps draining your battery so they can scoop up and market whatever information about you they can. Battery life has also been impacted by the BLE tracking features, which run all the time.
I wish I could upgrade the Nexus One with a 5G radio -- it would be a great phone today.