They are a fantastic species to work with. Mine has the calmest disposition of any snake I've ever met (though she started out a little jumpy). I literally fell asleep holding her last night and she never even moved. They're also very slow growing, so you'll have plenty of time to figure out its adult enclosure.
I think you'll be totally stoked with whatever species you choose. You've obviously done your research and are prepared for your new baby, so I can't wait to see what you pick!