i was "forced" to switch from a Palm Pre (it died after it fell on a rock and the screen broke, i was trying to save my upgrade for a Pre3 but it didn't come out in time) for a NS4G and i have had more issues than likes.
1) Battery life SUCKS! i only charge it about 4 hours (from Midnight to 0400 as the Sprint rep suggested to only charge it for 4 hours), and when i get up in the morning it has full battery, by 12am it is dead, completly drained and i a m not a heavy user. i just browse the internet here and there, stream some music on my way to work (while plugged in to a car charger), and maybe check a few E-Mails. i just can't believe the battery dies so fast!
2) the most common problem, SIGNAL! at my house my Sprint Pre would have 3 to 4 bars constantly everywhere in the house, and now the NS4G has either one bar to NONE! WiFi is the same issue, even i am 5 feet away from my router it only shows 3 bars on wifi and if i go to my room it drops it.
3) When streaming Pandora (not over Wifi and not in my car using bluetooth) if i forgot that i left the Wifi and Bluetooth on and i shut them off, Pandora stops working, very annoying!
4) i don't like i can't take pictures very fast, like multiple shots, or back to back... i mean, with my Pre i used to just hold the Space Bar and it would continuosly capture an image, and with a baby who is about to start walking that comes in very handy!
5) i HATE! HATE the speaker not being loud! i have missed calls and text from important people and when i go look, the phone has the volume all the way up and it has a ringtone that i know it would be heard from any room in my house since it is the same ringtone i had on my Pre.
6) random freezes... when charging it usually freezes and the "X" logo shows up and i have to do a battery pull in order to reset the phone.
not everything is bad tho, i really like how light this phone is, and SOME apps are nice, nothing too impressive. i am using all the GO Apps (GO Launcher/ contacts/ mesaging...)