I'm on Sprint with a Samsung Moment, forever stuck on 2.1. The Moment was officially dropped by Samsung 9 months from release with the only recent update being a fix* to the radio driver because the CDMA radio would die so badly it couldn't call out (including being unable to call 911...an FCC violation) and it required a reboot to fix.
Sprint has been known to replace it for free with an HTC Hero if you throw enough tantrums and demand enough replacements of the same model, but really, Samsung is to blame here. I will never own another Samsung phone and have prevented others from buying them as well. I've personally given up hopes of the problem ever being rectified, but I'm switching my family to Verizon/iPhones at the end of my contract.
* It didn't really fix anything. The radio still dies randomly, just slightly less often.
Sprint has been known to replace it for free with an HTC Hero if you throw enough tantrums and demand enough replacements of the same model, but really, Samsung is to blame here. I will never own another Samsung phone and have prevented others from buying them as well. I've personally given up hopes of the problem ever being rectified, but I'm switching my family to Verizon/iPhones at the end of my contract.
* It didn't really fix anything. The radio still dies randomly, just slightly less often.