I have been using emoncms.org for what seems like a couple of years (but is really only a year) and like it a lot. I was using Smart Energy Groups for a few years before that. SEG has some really nice visualizations and some interesting ways of handling data. It is perhaps not as flexible as emoncms. SEG has defined types for the inputs/feeds (all inputs are feeds, though there can be calculated feeds). This has the advantage that it knows if values should be aggregated or averaged when changing time resolution. It does not seem that emoncms has this capability so it is easy to get misleading graphs when the sampling rate is too low. As an extreme example, I have a septic tank pump that comes on about once a day for less than a min. This load does not always show up on the graph. With SEG, it would show up which was very helpful, even if the power level (watts) would likely be somewhat misleading.
Similarly, I could look at energy utilization over time much easier. I have seen the 17-step method to get the universal graphing module to show daily energy use and have that on a dashboard somewhere. But, it seems complicated to set up and use. SEG had a really powerful dashboard creator that was very easy to use. One additional thing it had was a widget that would show metrics about a particular feed, i.e. daily high/low, current value (useful for temperature and power use), another one had a lot of metrics useful for power of a circuit, like today, yesterday, last week, this month, last month.
Have you thought of adding anything like this?