Solas and Cassandra are my benchwarmers. Cass can come along sometimes, and some of my quizzies like her and consider as best friend, but I find her a bit boring. I prefer her casual side which comes up more often at home after you get to know her better. I also like how deep she can be, but haven't seen that come up in the field - I'm seriously missing out in case I'm mistaken. Actually I appreciate slowly and carefully thinking personality, but more spontaneous reactions of some others are just so fun, and make more balanced motley crew for my (intentionally) "boring" main character. My less "boring" one adores her yet often replaces her with Blackwall since they're friends too.
Solas, I just can't like him. He's the type that ticks me off, and I'm so rarely ticked off by people or characters that this feels bit odd and not completely pleasant. Solas doesn't seem to really care about people, as they are, and when he gets passionate about something it's a topic I'd rather approach coolly.
I haven't even got a chance to punch him yet. My Cadash is trying to be friendly with him since he's curious about magical stuff, but I felt distant about that relationship. My initial playthrough Lavellan found Solas kinda suspicious, not to mention seeing him practically as rival (because some comments about elfy issues came off rude, and I wanted to be the winter&spirit mage of the group), and ended up acting just mellow with him to keep certain polite distance, but Solas took that as friendship (for the first time being diplomatic in a game felt like a weight to me). Don't know about my Adaar yet at this point, she should fall for Sera and overall not overlap with previous Heralds too much... Maybe she'll take Solas always along to keep an eye on him?
Excellent character but bit distressing to handle for me.
Maybe we get a chance to treat him as a villain in future, hopefully. (Or become a villain for him due some dark character developement - I'm apparently not at my best when dealing with him.)