I have a European (GSM) unlocked Pre 2 with webOS 2.0.1.
Very often it happens, that after leaving WiFi zone (my house), I have 3G and decent signal strength, but internet is not working. Some apps report DNS error, some timeouts.
Workaround is to enter airplane mode and leave airplane mode. After that, everything is fine.
I was using the same SIM card before with my Pre Classic with webOS 1.4.5 and never had these issues.
I guess, it is not a hardware fault, but a bug in webOS 2.x.