Bound Bow is an extremely powerful bow, especially considering how early in the game you can obtain the weapon. However, I did a quick simulation play-through to get to level 14 using ~ and coc'ing for the DB armor, afterwards simulating my test via 'Golden Claw' and I wasn't too sure on its viability for a few reasons.
Long story short, I feel that for the assassination game play, quiet casting is almost a necessary evil [I personally hate illusion magic, and would have no idea how to level it up.] in order to effectively play an assassination archer based on Bound Bows. So I ask you, is it worthwhile, going 51 points into Conjuration, AND 50 points into illusion to use the bows? How quickly does Illusion magic level?
So, as for the power of the weapon, I'm more than convinced its a great addition and worthwhile to go into the Conjuration tree specifically for an Archer's purpose.
HOWEVER, in the assassination play style it can be burdensome. On my run through of Golden Claw, I noticed that even with 40 sneak, I was being looked for entirely too much. On my previous game play at 40 sneak I could walk up to someones back, pickpocket them, lunge, miss, and re-lunge for the kill, without ever being anything less than 'hidden'.
When I recast my bow, however, enemies were seeing me from annoyingly long distances. Unrealistically long distances. Through walls, distances.
My specific example is me nearing the end of the first section of the Golden Claw cave, and the Durdge are standing like statues in the little imprints on the walls. I killed them, and I knew the next kill was two turns away, so I refreshed my bow to ensure it didn't run out on me. Imagine my surprise when I recast it, and I was being looked for by three of them, so many curves and bends away. Of course, they didn't find me, and returned to their original spot, but none-the-less it is annoying.
Here is something that I learned / discovered about the Bound Bow.
It is nearly as powerful as an non-exploited legendary Deadric with Deadric arrows, which is very difficult to obtain or keep a healthy level of until late game [This of course isn't including enchantments].
Bound Bow = 36 Damage
Daedric Bow = 29 Damage
* Under the assumption you aren't abusing Smithing to tell via Fortifying*
100 Smithing = 11~ Damage to Bows
Legendary Bow = 40 Damage
Leg. Deadric Bow + Eleven Arrows = 56 Damage
Leg. Deadric Bow + Ebony Arrows = 60 Damage
Leg. Deadric Bow + Deadric Arrows = 64 Damage
Bound Bow + Bound Arrows = 60 Damage

I loved him too. I wish I could have kept him forever but then he turned into a pile of ash 