Microwaves have immense potential in biomedical and clinical applications for monitoring and diagnosis of biological tissue and their properties. Vector Network Analyzer (VNA) is a key component for these microwave measurements. The accuracy of a microwave monitoring system depends heavily on the capability of VNAs. Apart from measurement accuracy, the size, cost, radiation power, power consumption, and robustness are other factors that need to be considered for choosing a particular VNA for biomedical applications. This paper presents a thorough comparative analysis of two commercially available VNAs, Agilent Technologies 8720ES S-parameter Network Analyzer and PicoVNA 108 by PICO Technologies. The 8720ES VNA operates at 50 MHz to 20 GHz whereas PICO VNA has an operating bandwidth of 300 kHz to 8.5 GHz. Firstly, parametric analysis is presented which compares both VNAs in terms of their statistical features. Thereafter, extensive on-body measurements are conducted using two standard antennas. Additionally, In-body measurements are also conducted for further investigation of the matter. Numerous multifold measurements on both VNAs provide a strategic comparative analysis of both VNAs.