If interference is bad a different radio will not offer much help. A more sensitive radio (Whistler for example) will be worse. It's not a matter of the radio but a matter of reducing interference. A higher end general coverage receiver may help. You're looking at something much more expensive like an ICOM 6800 for example. Filtering the antenna system can help. Notch trouble frequencies, filter mobile phone networks, etc. But if it's radio hash coming from electrical equipment you have work to do. Since the worst will be near you, start looking at home first. Noisy power supplies are EVERYWHERE in the modern home.
By high UHF, are you referring to the UHF T-Band (470 to 512 MHz)? I'm in the North Shore area, and I never had a problem receiving anything in that band while using my SDS100. I agree with the above post that there's many factors that may contribute to your issue. Also, agencies in many cities, including Chicago, have reported issues with the UHF T-Band ever since DTV channels started changing frequencies. That's why the Chicago Fire Department is currently using the city's 800MHz P25 system, and eventually will switch over to 460MHz due to issues with their T-Band freqs.