Hey there- let me try and answer the call here..
All 3 units feature the same 5-in-1 sensor with internal solar powered fan aspiration standard.
The 1015 and the 1500 are mostly the same, only aesthetic differences for the most part. The 1500 has cpacitive touch operation buttons, the 01015 has standard operation buttons. Both feature the weather ticker scrolling text display, which delivers all kinds of extra and relevant weather records and current data- lots! Both also feature a backlight, today and all time records with time stamp, customizeable alarms, AC powered and/or battery power/backup.
The 01010 has all of the same current data, but is a slightly less expensive unit, so it has no weather ticker display, no backlight, no AC power option-battery power only.
You are correct that none of the displays give any rainfall charting, Rainfall data consists of Event (most current rainfall event total), Month total, and all time total. On the weather ticker, other rainfall info is given, such as "days since last rainfall" weekly rainfall total, current rainfall rate, etc.
The great thing about the bridge is that it is completely independent from the displays- our sensors connect directly to the bridge (and also trnasmit to the display at the same time if you wish). THrough the web portal site you can chart the rain and display and save out actual graphs, and you can publish your sensor data through wunderground. We are in talks with several other weather software sources as well. The app then allows you to monitor conditions remotely as well. You can set and receive email/text alerts for Wind, Temp, Humidity, Rain, Pressure as well. ANy changes you make on the app or web portal are reflected "globally" in the other. Mostr of our other sensor will also connect to the bridge- I have a floating pool/spa therm, a 5-in-1 sensor, a 3-in-1 sensor, and a few basic temperature/humidity sensors throughout my house and property- including the fridge to make sure my beer is always the right temperature of course!
I hope I was able to answer your questions, let me know if you have any more. I sure enjoy havinbg the 01500 display at home, and the internet bridge gives me allot of options and flexibility- I have had almost as much fun developing it as I have had using it every day for the last few months (alpha, beta test;-)