When comparing UTHash vs GLib's GHashTable, the Slant community recommends UTHash for most people. In the question“What are the best open-source map/hash-table libraries for C?” UTHash is ranked 1st while GLib's GHashTable is ranked 8th. The most important reason people chose UTHash is:
UTHash is released under the BSD license, which allows its redistribution even for commercial use.
Ranked in these QuestionsQuestion Ranking
Pros
Pro BSD license
UTHash is released under the BSD license, which allows its redistribution even for commercial use.
Pro Well documented
UTHash documentation is detailed, well organized and uses plenty of examples.
Pro Easy to use
UTHash is straight forward to use and is easy to install.
Pro Very fast
GLib's GHashTable is one of the fastest overall of the open source implementations you can benchmark. It has low memory use as well.
Cons
Con Not the fastest/slimmest option
There are other options which either show better performance characteristics or better memory usage (as in overhead per item), or sometimes both. Specific comparison micro benchmarks including plots for the data can be found here.