Nitro Pro is the recommended third-party PDF document solution certified for use in dvmCLOUD and continuumCLOUD. Release 10 (and above) of the software loads slower than previous versions due to a new plugin that is turned on by default. If you are not using the Evernote functionality, turning off the plugin will make the software open much faster.
The next time Nitro loads, it should open in approximately half the time.