The Pro-106/197, as of right now, will scan all public safety that is not encrypted or using unsupported digital formats like ProVoice. This means that it will follow Denver EDACS ESK, Aurora EDACS, DTRS, MARC (Denver will transition to this in the future), FRCC, Westminster FD, and anything analog.
There are some users who have seen some limited testing of P25 Phase II TDMA on MARC and FRCC which the Pro-106/197 will not be able to monitor. So far, it's solely isolated to radio tech talkgroups and it is unknown if/when Phase II will be rolled out onto these systems. As far as DTRS, there hasn't been much talk of Phase II as of yet. If you can find a good deal on the Pro-106/197 or the newer RadioShack Pro-651/652 (there's plenty of posts in the RadioShack forums), then I would definitely suggest picking one up. It may be a good idea to consider a Phase II scanner if you're looking to be fully future proof, but is not necessary.