The ARMER system is digital, but there is also quite a bit of non-digital stuff you can pick up. The north/west areas of the metro area are mostly on the ARMER system, but the south/east areas are still mostly on conventional VHF/UHF. Where exactly are you going to be in the area?
Here is a link to some good info about the area: www.geocities.com/mn_metroscan
Also just so you are aware, mobile scanning is illegal in MN unless you have a ham license. If you plan on having it in the car with you, keep it out of sight and don't get pulled over.