Another thing to consider is your watering habits. Terra cotta allows more air to breath and allows th emedia to dry faster, wheras plastic retains moisture. If you are heavy handed when watering, the terra cotta will allow more to the roots and help prevent root rot.
When people ask me if they should grow in plastic or clay pots, my standard answer is, YES! Mainly because those are the only two kinds of pots readily available. I think there are advantages and disadvantages to both and many different factors can come to play in determining which will work best for you. Some would even say that NO pot is best when growing orchids.
Most everything that can be said has been. It depends on your culture as to what will work for you so don't be afraid to experiment a little. Like most people I put my cattleya types and dendrobiums (the ones that like to dry out) in clay pots. I also use clay pots with sphagnum moss for my cool growing maxillarias. The clay tends to wich the mosture from the sphag. I think as it does this it draws air down through the pot keeping the root system cool. It seems to work for me. And also remember that everytime you change how you grow its like learning all over again. I went from window sills to lights in the last few years and now Im about to make the jump to a greenhouse and it'll be like starting over.
I am new to orchids, I've only been at it since September, So hello to all, and over time I hope I am not going to be a pest with questions.
teddflyfish