I find that those types of bets offer the most value.
You can ask any idiot how is the LAkers ATS, but they couldnt tell you what their record is ATS 1stH.
Also they are some great trends that I have noticed, such as Cavs games go over in the 1stH alot. Actually I dont know the last time they played an under 1stH.
Clippers have been a great first H bet, but fade 2ndH. Especially on the road. Their FirstH go over too. They actually went 2 weeks of games worth of 1stH overs.
Cavs didnt cover a FirstH for about a month. They just recently started giving a tremendous amount of effort, as they have become a laughing stock.
The Thunder dont play any defense until the 2ndH. There firstH are very faced paced, and usually them and their opponents score a lot of points.
I bet alot of halves, but cant say thats all I do. It account for over 50% of my bets in NBA though. I found a good website/blog that tracked ATS and O/U trends for halves but they haven't updated since December so its not as useful anymore. I still use it sometimes though just to get a starting point. http://raregamblinginfo.blogspot.com/