Yesterday we finally upgraded our sites to 1.6 (it's been sitting in the repository for a while), though we had to face some difficulties with the Web Deploy process.
First of all we tried to build a precompiled package (we ended up with doing it oldschool mode, though). One among other things you should watch out for is that the build process throws an error for files included in the projects as "None", instead of "Content". We had to fix ~50 errors like this in our themes and modules. :)
So we're sticking to the regular Web Deployment process in Visual Studio for now. Using 1.6, you may end up getting the same error about the file "\Media\web.config" as we did, described in this issue report (includes fix).
Aaand there's more! By default, the deployment process tries to apply the local ACLs (Access Control List) on the resources on the server. In our case the server (by GearHost) doesn't allow that (why would it), thus the deployment process gets stuck. To prevent that, you have to dig into Orchard.Web.csproj:
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' "> ... <IncludeSetAclProviderOnDestination>False</IncludeSetAclProviderOnDestination> <!-- Add the line above --> </PropertyGroup>
The update giveth, the update taketh away. Hallowed be the update!