The Bamboo and the Trent are VERY comparable at inception. The Trent is maybe a tiny bit smoother, but the difference is not very noticeable.
But the Bamboo deteriorates. I noticed after a couple of weeks it would not be as smooth as before. It deteriorates over time, so you don't even notice at first, but if you pick a new one and compare - all of a sudden it hits you, how much less smooth they get, over time.
On the other side, the Trent has two problems. One, it is short. Some people are bothered by that - I am not, personally. But if stylus length bothers you, then this might not be a good solution.
The other problem is the idea of sticking a sharp pointy object on the other side of it. The point of the pen can stick out just a tiny bit if you are not careful at rotating it all the way inside - and if you pick up the stylus the wrong way, there goes your iPad screen. The solution is simple - just take the pen out. I was fine with that, but, if you are planning to use it as a pen as well, then you might keep this in mind.
Yet, I am willing to live with all of this because it is the smoothest writing experience I have had on an iPad - and, after a couple of months of use, I see no deterioration. Every rubber-point stylus I had became less smooth over time.
Penultimate... it isn't pretty. It has no fancy functionality. If you plan on doing anything but simple handwriting, I would not recommend it. But for writing, the feel is just the closest to paper I have experienced. The smoothing is kind of on the 'high-side', so if too much smoothing bothers you, it might be an issue. It feels just right to me.
It does, by the way, integrate with dropbox and evernote, if you care about having your notes easily available off your ipad.