I was using a ScanGauge II for a long time and liked it but I switched to an UltraGauge because I wanted to monitor LTFT and couldn't seem to get the X-Gauge for that programmed right. Plus, the ScanGauge II only shows a max of 4 gauges at once and the UltraGauge can show up to 8 per page.
The downside to the UltraGauge is that every time I start my car the MyLink starts at the beginning of my flashdrive music, with the ScanGauge II it would pick up where it left off which was nice.