Well if your issues are upgrading and migrating then MODX cloud will do both of these in a single click with snapshots you can make a copy of your full site and start a new one or share with any other MODX cloud user and MODX updates are a one click thing on cloud.
Signup for a free lab account and play around with it you might like it.
About the only real advantage to using Cloud for dev is you can show it to your clients or anybody else (for help, for example), which you usually can't with a localhost installation. And if you have a team working on the site, of course.
As far as moving a dev site to a prod site, you can use Vapor on any installation. Make a Vapor package of your dev site, and use it to migrate to any other installation. It would be nice if we could figure out where the php binary is so that it could be done via SSH, but a newly developed site shouldn't be too big to work via HTTP.
Just follow the first half of the Vapor instructions on your dev site, then download the package from core/packages and put it in your new installation's core/packages and install via Package Manager like any other package.
https://modxcloud.com/userguide/how-tos/import-sites-with-vapor.html
That is the way I do it. I just put the zipped Vapor package (from the Cloud installation's core/packages) into my new site's core/packages, then install it from Package Manager like any other package. The only trouble I've ever had was if the Cloud site was too big to get packaged in the first place via HTTP.OK thanks. So maybe the fact I get repeatedly asked for a username and password when i try to install via Package Management could be due to the server not allowing large zip files to be unpacked?