If you're just interested in cycling, probably wouldn't justify the cost and the annoying and relentless showing of adverts.
There's too much motor sport for my liking, and bloody equestrian events, but it's included in out TV package so doesn't cost any extra.
I prefer Norwegian Eurosport compared to the ITV equivalent channel on the box here, it's just jingoistic and biased.
There are a few cycling channels you can stream, I believe, you just have to surf a bit to find them: this is one of them, but I think you may need to subscribe.
http://www.cyclingfans.com/live_race_coverage