Due to their small size and atomic clock performance, rubidium oscillators have been used as holdover oscillators within test and measurement, defense and communications industries. Most recently, they have supported demanding timing requirements for the 5G telecom and financial industries. The Miniature Atomic Clock (MAC) rubidium oscillator was developed to provide these industries with a miniaturization solution. By leveraging the low power and small size of vertical cavity surface emitting laser (VCSEL) technology, the rubidium oscillator designs could be improved accordingly, without compromising performance. The second generation of this technology utilizes advancements in low noise electronics, micro-processing and miniaturization. With these advancements, the MAC performance has improved to address more environmentally sensitive applications. This paper will measure its performance and compare it to predicted behavior for a variety of mission scenarios.