Since their introduction in the early 2000s, gallium nitride transistors have emerged as a replacement for the traditional Si-based MOSFETs in power electronics applications. In dual-stage LED drivers, a solution to keep the converter simple and to regulate input and output parameters at the same time is to integrate both stages. The main drawback of this technique is the higher stress in the main switch, which can reduce the efficiency of the system. This paper evaluates the pros and cons of using a GaN transistor as the main switch in an integrated topology in an attempt to reduce losses. This is made through a comparison between Si and GaN switching devices in an integrated double buck-boost converter designed for LED lighting applications. Three different switches were tested at three different frequencies, ranging from 50 kHz to 150 kHz. GaN based converters presented higher efficiency and lower operating temperatures in all the cases, with an efficiency gain of about 5% in comparison with their Si counterparts. Loss distribution of the converters shows that the limiting factor in the overall efficiency are the diodes used in the converters, which account for about 50% of the total losses.