We've been using the product for a few months now after have looked at most of the alternatives. The biggest differentiators for me have been:

1. Really straightforward, scriptable installation 2. Intuitive view of the log data 3. Very quick and easy to select a time frame 4. UI is oriented to cope with lots of server creation/destruction (very useful for auto-scaling environments and not well handled in some of the other products)

We are very happy with the product - great job guys!

Mainly the 3 items we mentioned above.

Technically, building a scalable infrastructure to ingest an order of magnitude of GBs more than other platforms was a bit challenging (and still is) but I think we're on our way to achieving that.