The h4150 can use with GPS but it won't be really smooth especially if you plan to use it heavily as 64MB of RAM on WM2003 is not quite enough for heavy usage. However you can cut down on RAM usage such as removing today screen programs & other applications that install into the main memory (RAM).

By the way, the more channel a GPS receiver has the better the reception signal. Furthermore, one need to consider the chipset of the GPS receiver too where a good one should be using the SiRF Star III chipset.