Paket ist an NuGet Alternative since "NuGet is broken by design" (statement of the NuGet Team itself: http://blog.nuget.org/20141010/nuget-is-broken.html)
There is a good alternative called Paket:
The only thing you have to do in order to support Paket is to drop the usage of install.ps1 which is already declared deprecated by NuGet. I wrote a blog post about that:
Planned for PostSharp 5.0 (only getting rid of install.ps1 – not direct support for Paket)
We're reworked the plan last week and 4.4 is going to be scaled down and merged with 5.0. Work should begin in July, so we're one quarter late.
Note that in theory you should be able to repackage PostSharp yourself with relatively little work. An alternative is to use the "zip" deployment option that is now supported in PostSharp 4.3 but not yet documented.
Petter Brodin commented
Is this still on the roadmap for 4.4? I'm evaluating using PostSharp, and since we're currently tied to using Paket, this is relevant for our situation.