Yep very lean but very good. Never smoked any but I have made burgers and chili with it. It is awesome in chili. You will find nothing more tender.
I would think with smoking it for a long period of time you will need to be concerned about drying it out as it is so lean. Marinading it first in some marinade and spritzing quite a bit during the smoke may be something you would want to try.
From Buffalo Hills Bison
The one time I had it it was cooked in a slow cooker and it was great! I imagine of you keep a moist environment in your smoker and don't do too much to add flavor then cook it to temp you'll be just fine!