When I first started using YCharts, I like the fundamental charts with multiple metrics. Later I found Fastgraphs to be superior at much lower price.
I was really upset when the estimates chart depict the wrong presentation of actual vs. estimate EPS and revenue. Very often I could find stocks when the actual is lesser than estimates but YCharts estimates chart show actual to be higher than estimates. This is really bad and I don't expect this for the price I paid.
Just be careful that you do not assume the YCharts give you accurate data. You need to check to be sure if the charts are accurate.
I wish I could rely on Ycharts to tell me quickly whether a stock is at fair value by looking at their fundamental charts with various metrics plotted in the same chart. I also wished I could tell if the stock's future is in the uptrend with actual results beating estimates but the chart gave me the wrong info. (I have uploaded a screenshot of Google revenue estimates vs. actual chart. This chart show GOOG actual beat estimates for all previous quarters but this is clearly not the case)
Worse of all, I feedback this to their staff and insisted their data provider is reliable when I provided them evidences that the chart is showing the wrong picture. This is so unprofessional!