I have just purchased this - here is some feedback:
1. You should specify that it is the Google Maps JavaScript API that is required. There are 16 Google Maps APIs, and it took a few attempts to get it working.
2. Custom maps do not appear to be able to zoom in and out, only scroll. Can this be fixed?
3. The "Create New Hotspot" page has a lot of fields that not everyone may require, and may not make complete sense to the end user. Please allow an options page to enable or disable these so only the fields we want are displayed. For example, I do not need Address, Website, Thread URL, or Image URL.
4. Adding a new category requires an Icon URL and a Shadow URL (?). This is confusing, and a drop down of included pins would have been easier, including an option to upload a custom pin image.
5. Categories seem to be forming a legend at the top explaining what the different markers are for. It seems with several categories this will get messy. It may be nicer to have a proper Legend box below the map listing these more clearly.
6. It would be nice if we could click these category / legend names and have it display only these pins on the map.
7. Current Markers, Latitude, Longitude, Zoom would be better placed below the map, not above it.
8. If I add a category specific to a node map, it should only be listed on that specific node map. At the moment it also appears on the default /hotspots/ map when creating a new hotspot.
9. The Node category listings are sparse - they look ugly.
I hope this helps - I do not feel ready to put this on my live website just yet, but the above improvements would go a long way to making this more user-friendly. Thanks!