I bought a Smappee a year ago and it has been a great help in finding appliances that needed some attention.
Appliance learning has been a bit fuzzy. I’m missing a way to diagnose based on phase data. It can’t detect multiple stoves of the same type even if they are on different phases (I’m not sure there really is a way to do it though). And it tends to group always on appliances into a single appliance that was driving me wild for a while until I figured that was the case.
Data history is limited to what is stored on the service. You only get 5min granularity for the last day, 1 day granularity for the last 6 months and 1 month for the last few years. The UI for looking at that data is terrible.
The mobile app works fine, it does have notifications for appliances, but they are flaky. The added smart switch does not suite me, as it’s just the one and limited to the area where the Smappee meter is – but it might come in handy for certain applications.
Reliability was not a issue at all, it has been constantly working for the last year without any mayor issue. If it loses power it takes a couple of minutes to sync back to the mobile app.
Support was great, I messed up my order and they worked with me to fix it within minutes.
Solar meter is available, I haven’t had the opportunity to test it out.
Hackability. I have the home version that is compared to their commercial offering quite limited. They have a web-based configuration utility that can be used to reset the memory, make it re-learn the appliances and look at second-to-second data for each phase. Here is a example how that can be used in a chrome extension. The smart plugs can also potentially be used in the same manner.