Not sure where you are coming from, but you won't be disappointed, at least I can't imagine being disappointed. I live on the South Hill. Saturday I rode through town and most of the way up Mt. Spokane. I couldn't finish the climb (last seven miles about 10-15 percent with some steeper), but had a 71 mile day with 5,000 feet of climbing.
As for the South Hill, I live on the lip of the ridge above downtown. In six miles I'm in the country with little car traffic. I have a 24-mile loop through Hangman Valley, a 40-mile loop out near Valleyford, a 52-mile loop via Valley Chapel and Mt. Hope, and all sorts of variation in between and beyond. This doesn't get at the many possibilities for all sorts of riding.
There's also great mountain biking down the backside of the South Hill off High Drive, and Riverside and Mt. Spokane state parks, and so much more. If you move here and you're disappointed, well, I don't know what to say. I love it.
As a point of reference, I grew up in Seattle and rode a lot around there. I'm a member of Spokane's Bicycle Advisory Board, so we are working on making things better in and around town as well. There's plenty of room to grow as a biking city, but we've got a lot to offer.