Just in case others may run into this problem, I'm sharing my experience in successfully installing the downloaded version of FTM2014 yesterday (5/25/15). I have Windows 7.
Note: you can only purchase download versions of the full and upgrade versions from the Ancestry store.
The file downloaded just fine and didn't take all that long using Chrome browser, even though IE is recommended.
However, when I tried to install from the downloaded FTM file, I got this error message more than halfway through the installation process:
Access to the path C:\Users\computername\AppData\Local\Temp\setup.exe is denied
The installation just froze up. I closed the installation folder/cancelled the installation and started working on resolving this issue.
What I ended up doing is replicating the path from the error message, locating the Temp file folder on my computer and de-selecting the Read Only default setting, then starting the installation over and it finished installing in less than 1 minute.
You should double-check that your Temp folder re-sets itself to Read Only - mine did on its own.
My antivirus was turned off during the download and installation processes and, to be on the safe side, before installing from the downloaded file (it downloads to your "Downloads folder"), I right clicked on that file and selected "Run as Administrator" and then re-initiated the installation process by left-clicking on the FTM2014 downloaded file (again, it's in your Downloads folder).
There was no "next step" as far as having to install any updates, either. The installed version is 22.0.0.1383
FTM 2014 works just fine, my only FTM 2010 tree copied, intact, into FTM 2014.
I plan to save a copy of the downloaded file to a DVD to always have on hand. I hope that's do-able.