Seems like they're not the cheapest but the worst reputation part is definitely true. They were the first of the cheapest hosts and now new ones have sprung up that undercut Cogent's prices by oversubscribing.
What I've seen is the servers max out 60-70% below the 1000G/monthly limit so figure you can push upto a max of 2 or 3 mbps on em, after that your site will considerably slow down due to the congested burstable pipe and you will almost never max out the 1000G/month limit.
Now they're more or less good servers for starting out but guys this is something you learn from the pros, learn when to 'upgrade' properly and you'll have a happy business
Don't starve your sites of BW or speed.