If this was a 2-cour show, I'd be all aboard it as probably being a sleeper hit (btw, it's depressing to use the word "sleeper" for anything BONES related today). But, it's a rare 1-cour show (especially the short 1-cour, ie: 11 episodes) that doesn't end up being a train-wreck in my books, so I'm going into it with low expectations in the hope they'll be blown away.
Senko No Night Raid was the last 1-cour show I've seen that was good and used its time wisely, and UN-GO certainly gives me similar vibes, so here's hoping. It is a shame, though, that shows like this are never very popular (trying to find timely subs for Night Raid was impossible, and I believe its sales numbers were abysmal). So, while UN-GO may end up being another 1-cour trainwreck in the vein of Fractal, I'm just glad it was even given the chance to be on the air, considering it's probably not going to be a smashing financial success, and will definitely be giving it a watch.