Spokane Regional Networking, Social Media, Professional and Business Development
Just too many eggs in 1 basket for me. Separate installs may take a little more time but I think having them separate better allows for isolating issues, especially if your using a lot of add-ons that may not play well together.
Multisite can be a lot of eggs in one basket. But that basket can also be easily backed up. There is a lot of really cool functionality that can be used through premium services with multisite. Also through these premium services, sitemaps is fine.
Having a bunch of plugins running on a multisite install really does bog things down for all sites. But, I typically use few plugins and instead prefer to add needed functionality directly into the themes. So that said, functionality only runs for each site individually.
I have launched a few sites recently running on single site. And have launched other sites on multisite. If I need the advanced functionality, I use multisite. Otherwise, I usually don't want to add too much confusing functionality (super admin) for my clients if it is not needed.