I've been living in Gillette for about a year so far. Gillette is a beautiful small city, far enough away from any from any major city that it has a genuine country feel to it. Finding a job here isn't particularly difficult, but you might not have a lot of high paying jobs to choose from, either. There's a decent selection of stores to choose from, including a Walmart Supercenter that should cover most of your needs.
One of the best areas in Gillette is McManamen Park to the north. It has a big lake in the middle and is a beautiful place to take your dog or spend some time with friends. Summer weather is usually pretty mild and tops out in the 60s or 70s. There are usually farmers markets during the summer, as well as some parades and local festivals too. Overall, it's a relaxing city that I do enjoy living in very much.