Annie, this is a Canadian company, and I think they are reliable. But I didn't see any cheap tickets on their site, the price I got was over $100. Did you get cheap tickets through them?
Piogaw, lucky you to be able to use the RENFE.com website to buy tickets. For people in the US and Canada, it is frequently impossible to use their online ticket service. It has to do with the RENFE system not accepting a lot of US credit cards. In 12 years of Caminos, I have travelled on Spanish trains many times and only once was successful in using their website to buy a ticket. You'll see many threads on this forum about the frustrations of trying to use RENFE online.
There is a great, and very detailed, website on how to buy tickets on RENFE's website,
http://www.seat61.com/Spain-trains.htm# ... _for_Spain , but you'll notice that the author states:
"Buying direct from Renfe is the cheapest option, their site works fine for me and always accepts my credit card. But some people have payment problems when using Renfe.com, especially Americans or Australians and other overseas travellers, so before I start to explain Renfe.com's various quirks, just bear in mind that if you have any problems with Renfe,com there's an easy alternative,
http://www.petrabax.com/renfe. It's a private agency which has linked its site to the Renfe system, with the official Renfe prices converted to US$. There's a markup, of course, but it's worth bearing in mind if you have problems with Renfe."
Maybe some day these quirks will be fixed, but till then, for me the easiest choice is to buy from Petrabax, or to buy in person with my 40% off Carta Dorada for old folks.
Laurie