As i run debian testing i have a version installed via apt-get, it looks ok but since i have debian stable (my blog) for servers it means I dont use it as its not supported unless i install it by hand.
The documentation is enlightening and supports web servers well and i think looks usable with webroot at the zoo rather than just the one address per server that the hosting industry thinks best, i am not sure about postfix use but seems achievable with full certificate. but that is a bit like voodoo (my blog) to many.
I suppose i might install it on the production server non packaged and give it a once over but a lack of package is going to put some people off. I suppose the next version of debian will have it along with lame* audio support for captcha (my blog).
So dont expect to see a lot of lets encrypt hosts on debian soon unless there testing or it was installed manually which can be done in theory. I have tls sorted out for months ahead anyway.
*not rubbish but a new encoder