I've only heard good things.
I have two juveniles. They are still pretty light-sensitive at 2.5 inches, only coming out when it's dark. (You can get some kind of red light to see them at night, and it doesn't disturb them.) This kind of behavior often goes away as they get bigger, and they're more likely to be out in the open. They're very good eaters. Nhandu in general tend to be high-strung. Not necessarily defensive, but very easily startled and quick to run around. I have 3 N. tripepii as well, and they all act rather nervous. They're less ideal starters than Brachypelma and Grammostola, but doable as long as you are careful IMO. Care is not much different than any other NW terrestrial...hide, water dish, and it's good to give them an area of moist substrate that they can go onto if they want to. Just overflow the water dish a bit, let it dry out, and repeat. Nhandu do get fairly large, so plan your shelf space accordingly.
You could probably get away with it if you purchase a sling. Adults can be pretty defensive and skittish, and wouldn't be the best second tarantula. They are an incredibly stunning species though, definitely a must have for any long time hobbyist.
I've only had my GBB for a few months.
A few months, and you need another one already, bored w/this one? It MIGHT be a good idea to learn more about Ts before getting another.