Hello there all, new to this forum

I have just recieved a new 8520 curve on my upgrade from O2.
I currently have a 8800 for around 2 and a half years... I dont have any problems with this phone and still think i can last it for another year.
From what i have researched, the 8520 doesnt have 3g or GPS.
whereas my 8800 has GPS but still no 3g...sometimes i do use the gps...
The 8520 has a WIFI which i wont use...as i am always travelling.
1 problem i have faced with my 8800 is that when im driving and a lorry, bus passes or i pass under a small bridge, then the phonecall cuts off...
I am not sure this is a problem with the 8800 or is that generall in all phones(bb's).
So my main reason for upgrading to the 8520 would be for this phonecall cut off reason...Is there any difference or improvement in the 8520 that could solve this issue... or does the 8520 have better phone quality, reception then the 8800..
Thank you