I enjoy both.....solo for my own entertainment, as well as in a group setting.
Ukulele groups - The social interaction with my ukulele family. The group energy & fun. All of my ukulele groups involve some teaching aspects, so I learn a lot. Getting up the courage to play in front of the group is building my confidence as a player & mediocre singer. I arrive with a smile & leave with an even bigger one.
Playing in my church band - Pushes my boundaries in playing with a small group. Timing, tempo, chords & songs that are new and often challenging. Plus the overall worship experience in a wonderful & fulfilling way.
Solo at home - I can get lost in music at home. I can sing with loud abandon at home, and my dog doesn't complain. It helps me relax & de-stress. Home is where I take the stuff I learn from my groups and really work on it. Practice in my own space & time.