I like Leiber. He obviously has a solid offense to back him up. I know he has been out for like two years now, but he's well rested right, lol. But seriously, I hear some guys throw harder than they ever have when they come back. I don't know if that is the case with him, but I know he has been pretty effective thus far. He is a guy that you can get cheap and will give you decent results.
I also like Lieber. He has great stuff and is throwing harder than ever. I think he is good to have in a rotation. He had a couple of shaky starts, but he is still an overall great pitcher. I also am not familar with Garland.
Lieber's pitching on a monster offensive team with a good pen behind him. Should be good for plenty of wins. He's not likely to deliver anything beyond ordinary in the other categories, but the wins alone make him useful.
Garland is strictly deep league fodder. Not the worst guy on the planet, but he's sure nothing special.