The town has its merits. The arts--especially museums--are quite good, as is a lot of the downtown architecture and housing in midtown (
gorgeous houses). It is an oil town after all. With that also comes its fair share of conspicuous consumption in terms of shi-shi restaurants and shopping if that's your thing. The oil industry has also brought in more diversity than you'd think, particularly people from the middle east. The music scene used to be great though fairly country oriented (with lots of blues, rock and swing influence and a big independent/DIY aesthetic), though that genre has certainly lost almost all of its vitality and I expect Tulsa's music scene has gone the same way. The philharmonic and ballet also used to be decent (could be still?) and tickets may be cheap and available enough to just drop in if you're interested.
In terms of big-city amenities, arts, culture, nightlife, etc. it definitely beats the South SF Bay area on all fronts except cheap, delicious Asian restaurants. But it can't compete with LA, SF proper, DC...
You can also expose your children to experiences like having horses, which is harder in cities, but contributes to well-roundedness in a variety of ways. You can even go to the museum in the morning and go ride horses in the afternoon because getting from A to B is easy.
That being said, it is a pretty conservative place, and it's a long way from anywhere that's not (outside of college towns), and it's a long way from anywhere that looks different except the Ozarks. You'd probably be fine as a non-surfing liberal atheist except dating could really suck. Life could also be pretty hard for various ethnicities and other sorts of minorities, but less so than most other places within a thousand miles.
WARNING: DIGRESSION
In my experience with many of these places though, a lot of the problems are with the mindset, both of the city itself and of individuals who kind of fall in line.
You can move to a big coastal city and feel the energy of the place--movers moving, shakers shaking--and it's kind of true but it can be very hard to tap into that energy unless you're already connected and have a fair amount of disposable income. If you want to do things, make things, start a business, paint, build boats, join a band, or whatever, it's a lot easier to do in a place where you can afford a garage and not live 40 min outside the city, and where you aren't slammed just trying to pay $3000/month in rent.
If you want to be an active participant in arts, music, crafts, etc. it is generally easier to do in a place like Tulsa or Salt Lake City. You'll have more time and perhaps more income, and networking is pretty easy when the networks are small. You may or may not outgrow the scene eventually. The downside is that people spend a lot of time bitching about how nothing is going on in their small scene or small city and how it'd be so much better to be in a big city with the famous people in their field, and this can be demoralizing to the more sensitive or inexperienced.
However if you want to be a passive participant, a spectator, then it's probably better to be in a city where you can go from gallery to gallery and drink wine and gossip, or if you have the cash on hand to see the luminaries in your musical genre of choice play every Friday night.