Data not very stable on 3g although speedtest shows DL 8mbps, UL 2mbps,  ping 23.    Fast = 3mbps

Sometimes web pages load slowly as if waiting for some response.    What's could be the cause?

I've noticed more than a couple of times,  when  data connection has no response.    The connection is 3 to 4 bars,  mostly 4 bars,  but it would suddenly go to zero bars for a few seconds ,  then go back to 4 bars

What's happening here?    Is it switching to another base station?      Are there any apps to allow me to keep tabs of what base stations I'm connected to and the quality of service (both voice and data)

Yes,  I'm using 3g only.  Was it OK after you switched over to a certified phone?      If on 3g network using certified phones,  do you have the problem?