It's not so simple as to merely say that the Century C91 Sporter is crap. There have been three and probably four genrations of this rifle and each has improved. Mine has been outstanding throughout at least 300 rounds. I haven't spent the time with it that I should. One really has to educate themselves to chose a good one and know which generation it belongs to. That information is available with a thorough search. You really need to know what you are looking at including the issues that have been mentioned as well as issues like bolt gap and ground bolts. If you have no idea what I'm talking about then you need to learn before considering this rifle.
As I've said, mine was spotless from the git-go and I have only improved it by changing the rollers to improve an already more than acceptable bolt gap to one that will make this rifle serviceable for many, many years to come.
Rejecting the C91 out of hand is a typical reaction that is probably good advice for lots of folks. But, if you do your homework and make an informed evaluation/choice and are willing to or have the apptitude to, if need be, work on a rifle, then you might find it a rewarding experience on a number of levels. I understand what Nalioth is saying, and all too often he is dead right. For the uninformed he gives good advice, but, it isn't always the case for everyone, and with some effort the C91 can be a valued rifle.
Proceed with caution and spend some time doing your homework.
I'll be cleaning mine this evening.