There are two major criteria I have for a Twitter client, given the way that I use Twitter.
1. Keep track (and hold on to a lengthy backlog) of unread tweets.
2. Keep certain tweets out of my main timeline but still accessible to me when I’m ready to go back and read them. (ie Not simply “muted” or “blocked”)
I discovered last year that Tweecha did one very well. Months later, I’m pleased to report that it also does the second very well.