The only time I've ever had a TWI system go sour was with a lightning strike. Very robust. The sensors are a problem but there was a recent posting for a wind sensor (I assume that is the one you are referring to and I'd snap it up). With Kev's work and eventually mine, there is likely to be a way of re-creating a temp / humidity sensor very soon (by spring?).
The RS-232 interface goes well into a USB dongle and from there, any of the software packages will work. I, of course, have a soft spot for Weather-Display. Inexpensive, a lot of support, Brian H. keeps updating it, and while a little weird to get some of the fine points ironed out, a whole forum exists for that.
I have a bunch (don't ask my wife how many) of WRL units around. The big thing is if they are configured for which wind head (theirs, RMYoung and Tex Weather (still in business but awfully costly) but absolutely no way to know what to do to the board and the firmware to switch around. Some have solar and the input to that is pretty simple if you are lucky enough to have that.
Their display cannot be beat. Green numbers visible from across the room in any light. Not wireless but still good. As I was saying if there is a problem with the boards other than the areas I mentioned, the stack of three that are in the case can be popped apart and another one can be swapped out.
Good luck. Let us know what you decide (and if positive grab that wind sensor) and let us know how you do.
Dale