Yeah, not so much. Microsoft promised the software would be generally available on 1st May, but I checked late last night UK time and nothing was there.
I checked again this morning and still nothing.
Until I checked David Musgrave's blog and found he had been supplied a direct link by someone at Microsoft.
While Dynamics GP 2016 R1 was downloading, I did a little investigating and I think the reason it doesn't show up for me is that PartnerSource presents itself as UK for me, whereas the link supplied to David was a northamerican one.
Thinking back I had similar problems when Dynamics GP 2015 came out and I couldn't find the link on PartnerSource or CustomerSource. That time around I amended the 2013 in the link to 2015 and it worked; this time changing it to 2016 did not work.
Hopefully, Microsoft will get this sorted out to so the downloads for Dynamics GP 2016 are available via the UK sites.
Microsoft Dynamics GP 2016 RTM can be downloaded here.