The biggest advantage is that the TRX-1 can monitor P25 Phase II systems, whereas the WS1040 cannot. If you live in or near a major metropolitan area, or regularly travel through or to one, whether on business trips, or visiting relatives or close friends, you're likely to encounter P25 Phase II. Without knowing your location (city, or county, and state is sufficient), we cannot tell if you are close to a system such as this.
Also, the TRX-1 can receive DMR and NXDN transmissions, which are becoming more prevalent for businesses & school districts, as well as some public safety users. The TRX-1 has the RadioReference database available on it's memory card; the WS1040 does not. While not the best solution, the TRX-1 is somewhat better on simulcast systems, though if that is a major issue for you, then you need to be considering either one of the Unication pagers, or Uniden's SDS series scanners.