I don't use mine often for two stroke glow engines but I tune a lot of four strokes and gassers and needed a good one. I went through four of them before I broke down and spent the money for a good TNC tach. I have tested a bunch of different tachs with it and found the tach/volt meter sold through Horizon is a pretty good one. Sometimes it doesn't like some light conditions but for the most part it works very well. The TNC is the best one I have found in a very long time but the Horizon would be my first choice for the cheaper units. The added volt meter is a big plus too.