I helped with the install of GPGTools onto a Mac this weekend. It brings PGP email within the reach of an advanced non-programmer Mac user. It should also support S/MIME email, but that looks beyond the reach of a non-developer at present.
- Painless, vanilla install. It was no different than any other Mac application.
- Reasonably good integration with the default Mac Mail app. It adds some buttons for signing and encrypting. It integrates the key storage dialogs into the default ap in a reasonably intuitive manner.
- Correct PGP implemetation. This is based on very limited testing, but it seems to do the job.
- Reasonably good integration with the public key servers.
- No manual. You are expected to figure it out by trying things in the menus and reading the FAQs. This is a failing shared by many Mac applications. It makes it extremely hard to provide any assistance by telephone unless you also have a Mac. I will have problems providing telephone assistance because I don't have a Mac with email.
- FAQ does not cover very much. The rudiments of install, send, and receive are OK. Things like "how can I use S/MIME?" or "how can I exchange keys other than through a public keyserver?" are not well covered.
- It's easy to make mistakes and mis-understand things because basic terminology used in PGP, e.g., "fingerprint", are used but not explained.
In net, it's a really good start, but needs some serious help from some good writers to fill out the FAQ and provide a simple manual.