SpaceX is blowing the competition away. Even the Chinese have said they can't match SpaceX's prices.
I'd like to have some reliable sources for that, because SpaceX said that the launch cost for a Falcon 9 was $35-55 million, than they revised it to $50-56 million, than they published the estimated launch cost ($54 million) for the still non-existent Falcon 9 v1.1 and stopped publishing the costs for the actual Falcon 9 v1.0. The only commercial launch so far was CRS-1: it's a Falcon 9 + Dragon mission that NASA paid approx. $133 million ($1.6 billion for 12 launches) and it carried just 15% of the advertised payload and it should be a discounted price (12 launches contract + secondary payload).
By the way, the launch cost for a Atlas V is $125 million, for a Russian Proton M (21 ton payload) $85 million, for an Indian PSLV (3 ton payload) $17 million, for an Ukrainian (3.7 ton) $14 million .
Masse to LEO: Vega: ~1.5 T Falcon 9: ~10 T Arian 5: ~20 T
Vega: 1.5 t (LEO)
Falcon 9: 8.5-9 t (LEO)
Ariane 5: 16-21 t (LEO)
Falcon 9: 3.4 t (GTO)
Ariane 5: 6.2-10.5 t (GTO)
Completely different rocket classes, hence completely different prices.
What is the cost per kilogram delivered into LEO? The Falcon 9 can deliver 13 metric tons to LEO for $54 million, or $4 million per metric ton. That PSLV rocket that you are quoting only puts 3 metric tons to LEO for the $17 million, or about $5 million (plus change) per metric ton. The $54 million is the quote on the SpaceX Falcon 9 web page if you want the source.
That link is about the still non-existent Falcon 9 v1.1, that's why I'm very dubious: it's just trash talking, smoke and mirrors. They said the Falcon 1 would have been the first reusable and cheap launch system, it wasn't; then it was the time of Falcon 5, it was never built; then NASA came to the rescue and fully funded Falcon 9, neither this time it was reusable, however they say Falcon 9 v1.1 will be: I'll believe it when I see it.
Just to point out, according to the original sheets the planned launch cost for Falcon 9 was $35-55 m for 8.5-9 t (2007), in 2010 it was already $50-56 m, now it's "under $60 million".
So being generous, i.e. SpaceX 2010 prices vs. PSLV 2012 prices:
Falcon 9 v1.0 | 8.5t-9.0t | $56 million | 6.22-7 million $/t
PSLV | 3.25 t | $17 million | 5.23 million $/t
Russian and Ukrainian launches are still cheaper. I don't know about Chinese launches, but I'd bet their cheaper as well...
It should be pointed out that SpaceX has figured out how to reduce the cost of its launches to the point that the subsidy needed for Arianespace to compete would be embarrassing and noticeable to EU members and their constituents. Keep in mind SpaceX is making their rockets so cheap that even the Chinese don't think they can underbid SpaceX.
Sources? Because India's PSLV has a flyaway cost of 17 million $ per launch and Russian launch vehicles are even cheaper. SpaceX said they were developing a reusable launch system, but until now they haven't.
New systems generate new problems.