WS-2902-ARRAY hands down for definite.
Not only will it be compatible with your ObserverIP and your WS-1000-BTH but you'll also have the capability of adding WS-2902A display console or WS-2000 display console (Ambient calls the WS-2000 a display tablet...that is dumb...it's a display and it is a console, it isn't a tablet as it isn't touchscreen).
Like you mentioned the Wind sensor is better. More dampening on the wind vane for more accurate tracking instead of flopping so much around. The anemometer also has a much lower take off speed so you can detect and report on very low wind speed.
The temperature and humidity sensors are also of a newer generation Sensirion series SHT3x which is the same as in the current Davis and Acurite stations...although the Ambient is an SHT30 and those others are SHT31. But definitely better than what was in the older generation WS-1002-ARRAY.
With the WS-2902-ARRAY you can also add optional bird spikes easily....you can't do that nicely with the WS-1002-ARRAY.
The WS-2902-ARRAY also has more modular and replaceable parts.
The WS-2902-ARRAY looks much nicer in my opinion.
With the WS-2902-ARRAY you'll be able to add additional sensors using the ObserverIP or using the WS-2000 display console.
I frankly don't know why Ambient keeps selling the older generation WS-1002-ARRAY as a complete station with various models. I understand keeping it as a replacement part....but not selling complete stations with it. I think it only confuses the customer. Especially where there doesn't seem to be a price difference or depending on complete model kit it can be more expensive than something with the WS-2902-ARRAY.
Once you get your replacement WS-2902-ARRAY you'll need to be sure to update the firmware on the ObserverIP. Then you'll need to select WS-1550-IP as the station model.
Here is another tip. Instead of buying a separate WS-2902-ARRAY you should get a WS-1900. It saves you $3 and you get a free display. Granted this display does not connect to the Internet but it will work as just a display, and it is a free display. You'll continue to use the ObserverIP to report to WU and AmbientWeather.net. Yep Ambient pricing doesn't make sense.
Cons of the WS-2902-ARRAY (compared to the WS-1002-ARRAY):
- Zero, I can't think of any reason to still have the older outdoor sensor array. Makes no sense why the WS-1002-ARRAY actually costs more.
For those people with a WS-100x display and no ObserverIP device the predicament is a bit more complicated. Essentially their only option is the WS-1002-ARRAY because the WS-2902-ARRAY is not compatible with those display screens. So they either replace just the outdoor sensor array for an outdated model or they have to throw away a working display console to get the newer better outdoor sensor array. The price is so reasonable for a WS-1550-IP complete station or even a WS-2902A station that I would not think twice, as there is much to gain.