Here are a few GPRs that are popular and have good reviews:
GSSI SIR 4000 - The SIR 4000 is a versatile GPR system that offers advanced data collection, imaging, and analysis capabilities. It is suitable for a wide range of applications, including utility mapping, environmental surveys, and concrete scanning.
MALA GPR ProEX - The ProEX is a compact and portable GPR system that is designed for high-resolution imaging of shallow structures. It is suitable for applications such as utility mapping, archaeology, and geology.
IDS Opera Duo - The Opera Duo is a powerful GPR system that offers advanced features for high-resolution imaging and data analysis. It is suitable for applications such as geophysics, civil engineering, and environmental surveys.
Radiodetection RD1100+ - The RD1100+ is a versatile GPR system that is designed for locating buried utilities and structures. It offers high-frequency options for improved resolution and is suitable for applications such as utility mapping, construction, and maintenance.
Maybe this list will help you make a choice.