I checked it yesterday, and mine shows the last 8 digits of the outgoing call, cutting off the first three numbers (the 1, and first two of the area code). I read somewhere that the MP3 player has a smaller display than other radios.
As for the price, it is $10.00 more for me, but you have to switch to a family plan, and the $10.00 makes the Onstar an additional phone. However, there can be a problem for some. I thought there would be a problem with me, since I currently have 900 minutes a month, and the family plans are either 700 or 1400. The 700 plan would cost an additional $10.00. Therefore, I would be spending $10.00 more per month, but receiving 200 minutes less.
If someone had a basic plan with 450 minutes, adding the OnStar would cost a lot more, but then you would obtain more minutes.
I did a run of all my minutes in the past eight months, and discovered that only in December did I come close to using 700 minutes during peak times when talking out of the IN network. So, it should not be a problem since most people I talk to have Verizon phones. (The cell phone is my only phone, I did away with a land line 4 years ago.)