I've lived in Houston for just over 3.5 years, we are British but moved here from Singapore and are seasoned expats.
The gun crime does not concern me on a daily basis at all. I know that most drivers are armed so I'm a careful driver and don't cut anyone up (I wouldn't anyway). I avoid a certain supermarket that allows open carry - I don't need to see an assault rifle while I'm picking up groceries - but friends who shop there tell me they've never seen a gun there. I've not seen a gun outside the range except on a police officer's belt and I know expats who have been here 15+ years who say the same. My dcs are at the British school and I know their friends' parents don't own guns, although I have friends with kids at local schools who ask about gun safety at home before playdates.
Life here is super easy. Everything is available and easy to get. Healthcare is probably the best on the planet - the medical center here offers treatments for illness like cancer that is available nowhere else. You can get a medical appointment at the drop of a hat. The system is very flawed but if you're lucky to have insurance it works well.
We have fantastic restaurants, great concerts, we're hosting the superbowl next month and we have the biggest rodeo in the world with 21 shows over 21 days in March - I have tickets for Alicia Keys, Meghan Trainor, U2 and Rick Astley coming up in the next few months. Kids can do anything, mine swim and do robotics, there's all kind of sports and activities and a feel that anything is possible.
Houston is the 4th biggest city in the US (soon to be 3rd) and is bigger than greater London. We live in a fab residential area with a village that you can actually walk round, it's one of the oldest parts of Houston with lots of charm. The suburbs (Katy, Cinco Ranch, Lakes on Eldridge etc) are well served with chain stores and chain restaurants but feel suburban.
Houston does have problems, there's a lot of homelessness with people begging at red lights, crime is high and you'll see daily reports of shootings but it's also a big place and we don't venture into areas with high crime.
How old are your dcs and where will your husband work? His office location will determine your neighborhood, an hour or more commute by car isn't unusual, traffic is crazy. Some people do an early day ie in the office by 6.30am and leaving at 3pm to avoid getting stuck in traffic.
Feel free to ask any questions you want.