I have installed both pressure tree southern pine and Mahogany decks. I found that the Mahogany works great. The deck is installed near a lake and receives quirte a bit of sun year round. I have had no problem with splitting or curling an have given the deck very little attention in the past seven years that it has been installed. It might be more expensive bu if you think of living in the house for a long time it might be worth it.
As for railings I have defered installling one as I prefer the view of the lake. I am considering steel cable as it would cut down the least on that view. I might even raise the property around the deck by installing flower beds to avoid the requirement completely.