For me to trust an installer, implicitly, it's best for it to be part of my software distribution's package management system.
This means that the package is signed and checksummed, it's included in the distro's bugtracking system, and is being downloaded from a known set of mirrors.
Your next best option is to provide a download, checksums, and signatures, with a well-signed PGP/GPG key. At this point I can at least verify that the content is what you claim it is (whether or not that's something I plan on running is quite another matter).
Even a git repo provides a SHA1 checksum of a given commit that I can reference.
By recommending I curl-pipe-bash something, you're sending me a FLAGRANT signal that your security practices are somewhere well north of batshit crazy.
I ran into this while evaluating RVM (Ruby enVironment Manager), which itself turned out to be a requirement (or at least facilitator) for properly using Ruby for, of all things, supporting a Chef (configuration management tool) infrastructure. So ... in order to get a better handle on our server infrastructure ... the recommended and default practice is to install crap via curl-pipe-bash.
That cost us about six weeks of going through the damned installer and its effects (documentation is really poor) with a very fine-toothed comb. And I'm still not happy using it.