Depends on the use case and the accuracy needed. Each sensor should publish their plus/minus specs, but a lot of people don’t read them.
If you need precision accuracy, I would look at the Kumostat wireless tags. These are very well engineered, have exceptionally long range, have an IFTTT channel and a good community-created ST integration.
Wireless sensors for locating items, logging and monitoring presence, temperature, humidity and motion events from anywhere with Internet access, on iPhone/iPads, Android devices and laptops. KumoApp Engine allows automation algorithms to be defined...
I have the first pass of an integration ready for Wireless Sensor Tags. There is a service manager SmartApp that allows you to log into your Wireless Sensor Tags account and reads what tags you have registered. You can then choose which tags to connect to SmartThings.
The main support so far is for the Wireless Motion Sensor Tags (temperature, humidity, motion, and open/close plus more). The moisture / water sensor should also work, but I didn’t have one to test. The other types of tags should mostly work as well, since their system reports data consistently from the different tag types.
You can get the code here:
I’ve tested it quite a bit locally, but there may be a few bugs left to iron out. I need a couple beta testers to verify.