Considering using Subdomains

I am building a site where I want my users to have city specific information – multiple cities, with all separate information contained within the pages.
Over time, I am hoping to have employees that maintain the specific cities.
I am assuming that subdomain multisite is the best way to do this.

My question is this: When my users go onto their city specific pages, I want them to be able to change their location and look at upcoming events and information for other cities. Is that a pretty easy and standard thing? The ability to jump from one subdomain to another as a user? I’m assuming it would be accomplished by a plugin of some sort – or can I use a drop down menu that is the same for all cities?