I love the Vlad Taltos books. They're very often quite hilarious, and cover a variety of styles which I find a lot of fun. It also means if you find you're losing interest, the next book might just reawaken it since it's likely to be written in a completely different way. Some are written like old noir detective stories, one begins with a literal laundry list from the protagonist, and proceeds to explain how each item of clothing got on it and needing exactly that repair or bloodstain removed, one plays out over a single meal, and one of the spinoff subseries is basically a Three Musketeers rewrite set in the Taltos world. I think Brust is wholly underrated, he's one of my all time favourite authors.
Not yet mentioned is the Pern Books by Anne McCaffrey. A huge long series, eventually covering thousands of years, if you like them you're in for a lot of fun.
Re Thomas the Covenant, I actually have a problem seeing that recommended to anyone without a caveat what you're in for. He's a bit more than unpleasant, he's broken and rotten and not a good man, at least at the beginning. This is a book that has a protagonist, not a hero.
There is one incident only about 6 or 7 chapters in that pretty much will make or break if you are going to continue reading it, when the protagonist commits a really vile act.