It comes down to what is most important to you, the Note5 is more powerful in the CPU and GPU department, the Note5 also has GearVR support, samsung pay, etc. The V10 has a removable battery and mSD card. Those are it's primary advantages over the Note5, in most other aspects it is verrrry similar, or not as good.
So if you dont ever see yourself needing 200GB+ storage on your phone, the Note5 may be more enticing because of the more powerful SoC, or maybe you are interested in a phone that can dabble in VR, in which case the Note5 is obviously a better choice than the V10.
But if you want to carry a 100GB music library or movies around on your phone, the V10 with its mSD card slot will be more to your liking. Or maybe you REALLY need an IR blaster, or removable battery is something you've come to rely on.
Also, the spen "bug" is fairly overblown, sure it fits in backwards, but it doesn't do so unless you aim it STRAIGHT on, any slight angle and it wont fit, as opposed to when inserting the proper directing it will fit in very easily because of the curved tip. And further, if you DO put it in backwards, it can be removed without damaging your phone. The only thing that will cause damage is if you try to remove the spen when it is in backwards forcefully. If you try and force it out, it will break the internal latch sensor. Which even if that IS broken, still doesn't break anything else on the phone. So even if the worst case scenario were to happen, it's not like your phone is rendered useless, it will still function as a phone, it just can't detect when the stylus is inserted or removed.