I meditate alone, I am a bit of an introvert so I like having my own space and my own time to do this kind of thing and also it lets me concentrate on meditating since I have noone around.
I think you shoad meditate alone or in group who are good at it. Some people are not good at it, so working with people who are not goof at it may anoyy you and distub you.so avoid people who nod good at it.
I prefer to alternate between both.Together gives a strong bond. You carry each other. The practice together feels different from alone. I also like to try new things like a course on meditation, good spreaking or yoga.