Title pretty much speaks for itself, I play solo rounds a lot, mostly due to not having many dedicated discing friends. How are your solo rounds different?
I have a lot of disc golf friends and I play with them as often as I can, mostly because disc golf is a very social sport and, like sex, it's always more fun to play with company. However, I play solo rounds at least three times a week because there's a course five minutes from my job that allows me to get in 18 holes on my lunch break.
My solo rounds seem to be no different than what others have said here. I use them as practice to work on my form and practice shots I wouldn't otherwise try were I playing in a tournament or tag match.