If you are already running on WordPress.com or considering the move there, then upgrading to their Business Plan makes the platform more like a true WordPress Managed Hosting company. But without access to FTP.
Also, WordPress.com uses a custom backend design, called Calypso. It's a beautiful interface, and fast. But the third-party themes and plugins you can install, like our gallery plugins, do not show in that interface.
So this means you will need to load the default WordPress backend in order to customize those themes and plugins. Calypso is nice, but it hasn't been adopted by the WordPress development community yet.
We are happy to share that we've gone through and tested NextGEN Gallery, NextGEN Plus and NextGEN Pro over at WordPress.com. And they all work!