Thanks for being such an important part of the QuickBooks family! I'm happy to see you're considering making the switch to QuickBooks Online. I hope you'll enjoy the added convenience and simplicity it offers for your bookkeeping. There are two payroll modules available in the Online version, giving you additional control over how you choose to pay your employees. As these are run on separate platforms, most historical payroll information isn't transferred over. For more details about this, check out this great article: What to expect when you switch from QuickBooks Desktop to QuickBooks Online
Despite Intuit trying to move everyone over to the cloud so they can ditch the desktop version, I would warn you that no, it does not operate the same way. It is not just a little bit different, it is a lot different. And there are some things you just have no control over at all because Intuit tried to be too helpful and built it all into the background. This is a product made for the masses, not necessarily for the accounting professional, although many do use it for the sake of being able to help their clients by accessing their files remotely. Yes, you can probably find ways to adapt some of your current practices, but if you have a chance to test it out, I would do so thoroughly so you know what you're buying. Especially test the payroll extensively. Personally, I'm not a fan. I will not completely switch from Desktop to QBO until they improve it drastically.