I didn't really care for Clara as a companion. Perhaps it was that it seemed at times the roles of companion and doctor got reversed and instead of the Doctor being the cocky one, it was the companion instead.
On the otherhand, I absolutely LOVE the three companions we have now. I'm not sure why people don't think they have enough screen time or work well. I think they are aces above the last doctor's companions for the most part.
Yaz has had a LOT Of character development IMO. She has a back history dealing with family, herself (and we had the episode that dealt with mental illness and showing her overcoming it and really was inspirational I felt in many ways with her story there) and other issues. She's intelligent and really a great companion, perhaps one of the best from what I've seen.
I also like the dynamic between Ryan and Graham. It's the rocky start but developing relationship...all at the same time where they are dealing with the loss of their loved one. That relationship has really cemented. In a way I see them as two sides of the same companion, both reflecting different issues of loss, love, and relationships from two opposite ends of the spectrum (old and young, husband or son, etc).
I honestly like the new companions for the Doctor.