I think that resales offer better value - especially if they are relatively modern. They have had all the "snagging" done, and probably are fitted with all the mod cons - like grilles, air con etc. Over there, like here, in England, it seems you pay a "premium" on a property if you are the first one in. Would agree with the comments about the company that is mentioned, as I've seen some of their agents at work!
When we were buying a place in Spain we shopped around quite a few agents. I avoided the very pushy ones. Mind you, I'm the same if I go into a shop over here and it has assistants that don't leave you alone after one polite refusal of their help!
Even when we had found an agent that we were happy with - one who took notice of our requirements and took us to the area where we wanted to buy - we still asked around as much as possible about them!! Ever the cautious one!
The best of luck with your search - but not advisable to limit yourself to only one company - and if you don't know the area well do some touring before you see the agent so you have a good idea of the area where you want to end up and that it has all the facilities that you want