Wirelessly posted (7250: BlackBerry7250/4.0.0 Profile/MIDP-2.0 Configuration/CLDC-1.1)
I've only noticed issues when speaking to people who are on GSM blackberries. For some reason, these devices tend to pick up quite a bit of background noise, which I find very distracting.
Not so much an issue with CDMA berries.
I've not noticed tinny sound or static.