GPS performance on ipad 3G without a data plan

I am interested in the 3G ipad but may not want to pay the monthly connect fee of $15. I am wondering how the GPS works if one does not have the data plan? i.e. might it work as well as a Garman for instance, setting aside voice turn by turn etc. So, will it acquire satellites as fast, will it update and stay locked as well?

Finally, does the assisted feature of the GPS chip require a data plan to perform its assisted duty

Thanks,

Shannon