Lived there for two years
Springfield has pros and cons. I'm personally more of a "big city" person, and I moved from Kansas City to Springfield for a job opportunity. If you prefer the city life, Springfield is probably not for you, but if you prefer small town life, Springfield is also not the best choice. It has the problems of a big city (inordinately high crime, traffic congestion) without the charm of a small town (anything you might like about small-town life, Springfield doesn't really have).
First the Pros:
Proximity to Branson. This is a fun place to get away to, and lots of great shows and the wonderful Silver Dollar City amusement park
Outdoor recreation: Springfield Nature Center is a beautiful oasis right off the freeway, where you can go hiking with the family; Nathanael Greene Park is similarly lovely
Battlefield Mall: Thriving mall with Macy's, Dillard's, JCPenney, all the great mall stores going strong
Antiquing: Several antique malls worth visiting, especially Relics (others to check out are Mike's Unique, Ozark Treasures, and Urban Flea Market)
Springfield Brewing Company: BrewCo was my Sunday night go-to, with live music, rooftop patio, craft beers, great service and awesome menu
Climate: This is of course subjective, but I don't care for snow at all, and in two years of living in Springfield I remember only one day of significant snowfall; also it doesn't seem to get particularly cold in the winters (20s is about the lowest, and that's rare); summer can be very warm, 80s and 90s, which I don't mind
Minor League Baseball: St. Louis Cardinals AA team, Springfield Cardinals, play in a beautiful ballpark called Hammons Field, downtown
Cost of living: My apartment was almost 1,100 sq.ft. and included all utilities except electricity, and in a safe neighborhood in a well-maintained complex, and was less than $700/mo to live there
Next the Cons:
Traffic: Even though the James River Freeway was completed just a few years before I moved to Springfield, it hasn't been enough to aid traffic flow. Springfield has some of the worst traffic I have ever experienced. I think the infrastructure hasn't been able to keep up with the population.
Crime: For a city of this size, Springfield seems to have high crime rates
Arts scene: Coming from Kansas City, I found the paucity of art galleries and performing arts venues to be disappointing, but not surprising. They have an adequate symphony orchestra and the Juanita K. Hammons performance auditorium, which hosts touring shows like Stomp, which is nice but as far as arts there isn't a lot going on regularly
There are certain qualities I look for in a city that are rarely, if ever, listed among filters or typical criteria. For example, I'm an architecture nerd, and I love the Art Deco and Googie styles. There are very few examples of these styles in Springfield, which was disappointing. Also, I enjoy driving a little more aggressively than most drivers in Springfield, and since the freeways are always clogged I don't enjoy driving there. Another thing I don't really like about Springfield is their downtown. Even with the square it feels claustrophobic, and other than BrewCo, I didn't venture into the downtown if I didn't have to.
Overall, I don't consider Springfield to be very picturesque. There are a few nice areas, like the Nature Center, but it has a very industrial appearance, and not necessarily in that quaint, old-timey way. I'm a visual person and Springfield didn't appeal to my aesthetic.
People there, kind of a mixed bag. Some are friendly, some are not, just like anywhere else. I will say this - it seemed as if half the people I encountered there were transplants, like me. People originally from all over live there; I've met residents from Tampa, Chicago, Phoenix, Wisconsin, Boston, California. So at least Springfield doesn't look at "outsiders" like they have three noses, because half the population has three noses, so to speak.
I was content enough living in Springfield. I would probably have stayed put if it weren't for a miserable domestic situation I had to abandon for my own safety, but that's another story. I enjoyed my career and dearly loved my apartment. It wasn't everything I love in a city, it lacked a lot that floats my boat, but it wasn't a terrible place. Most of my "happy" memories of Springfield mean nothing to me now since I had to escape, but for someone who is either single or in a safe, truly loving relationship it could be a decent place to create wonderful memories.
Best of luck if you choose to move to Springfield.