Jon, That's excellent that you are considering Sioux Falls!
I think the unemployment rate here is about 4.5%...
Here is the Wikipedia link for Sioux Falls... it gives some good basic info:
Sioux Falls, South Dakota - Wikipedia, the free encyclopedia
The unemployment rate of 11% really surprising me, especially for NW WI. Have you had a lot of major employers lay off workers?
Sioux Falls has quite a few transplants. The ethnic diversity is increasing as well, and I find that a very good thing!
SD has no personal or corporate income tax. Here's an interesting link I dug up regarding the taxes in South Dakota:
The Tax Foundation - Tax Research Areas > South Dakota
For an idea of our weather:
It's hard to predict... This week, we've been in the mid 70s... Ideal!!
We have the usual summer thunderstorms. We're in the northwestern part of Tornado Alley, depending on which description of Tornado Alley you use. I would say tornadoes would be slightly more common here than NW WI, but its a rare occurrence.
For winter... anything can happen

. Much like the other seasons... I would assume we would have slightly higher normal temperatures than you, and lower snow falls rates. We actually had a calm winter last winter, but we were hit with the very bitter cold. One morning we had a -40 ish (I think) for a low temperature. I've never experienced anything like that. I had to work at 7 am, and my car barely started.
Sioux Falls has great schools... The 3 public high schools are all great... I know Roosevelt and Lincoln were ranked in top high schools around the country, but I can't find the links...
Sioux Falls has a new elementary school - Rosa Parks Elementary, on East 26th. A new elementary school is currently being built (I think it's almost done) in SW Sioux Falls near 57th & Ellis Road. Another is planned in northwestern Sioux Falls... I'm not sure when this will open.
Shopping/restaurants are plentiful. Dawley Farm Village, which is a new shopping district on the east side of Sioux Falls, will house Target and Kohl's and numerous other tenants.
Downtown Sioux Falls also has many small mom & pop shops... lots of neat stores. Sculpture Walk is downtown. Small sculptures from artists all around the nation are featured.
Do you have any specific questions? I'd be happy to answer them.