As someone who went through this year ago… I can talk about my own experience.
Moving to the cloud has been a good choice overall. I’m very happy with the decision. I no longer need to worry about things like Apache, PHP, MySQL, etc. I no longer have to optimize the configurations for each of the systems for performance. I also no longer have to worry about things like firewall tuning and scaling for bot traffic etc. At the end of the day… it’s like using Gmail. I just simply use the service.
The hardest part of the experience was simply letting go. I can’t go play in the database anymore. I can’t go manually edit a file, etc. This was hard at first, but eventually I came to realize that at the end of the day I really did not NEED to. By not manually playing around in those areas, I’ve had better stability and easier times doing upgrades, etc.
If you can think of your site being a SaaS solution instead of just another script to install, you’ll have a much easier time.
Regarding the migration… Olivia and Marc have the process down to a science. They will communicate exactly what is needed, work with you to agree on a date/time to do the move, explain exactly what needs to be done, etc. In a nutshell, you need to upload a complete copy of your site files (so they have any uploads and 3rd party resources) along with an export of your database. They will import it and configure their side to handle it. You can use a temporary address to test to make sure all is good and once ready, change the DNS to their control to make it live to the world.
We arranged for our site to be taken offline at 3am while I exported everything and uploaded it to IPS. By 8am, I was doing my final testing and go live.