Yes, Gigablast is open source and i trust gigablast but privte.sh isn't open source. They said they will release code but from the past 1 year they didn't releas.
2nd reason is privatesh is owned by pia which is based in us. Since we all pia keeps logs about metadata it isn't secure.
Note: metadata is also important
3rd reason :
There is a lot more to develop
4th reason :
It has no anonymous view.
It is better to add anonymous view like startpage.
Startpage anonymous is more secure but i do not trust startpage because it has no source code.
Maybe in future private.sh could develop.