The only beef i can think with them is that they are so very close to balistic tips and I will never let one of those tough my magazine again. Talk about no blood trails. I bought them on accident for both myself and my son and we are 4 for 4 with no blood at all. We did find all 4 deer but it was because of good shot placement and the deer didn't go far.
I would say your in the minority here as I have heard very few complain about the blood left by a NBT. I use the NBT for my deer and antelope needs in a CF's and can't say I have experienced a lack of blood or any problems what so ever. To me they are an excellent bullet choice for my situation and I like the bigger holes they will produce for a thin skinned animal such as a deer. Personal Experiences are valuable and use them myself so I trust your opinion, just have never seen it personally.