Three things attract me to the new Surface Pen. First, it has replacable tips that add more or less friction to make writing on the Surface's glass screen feel like paper. Next, the top button on the pen acts as an eraser, mimicking a pencil. Finally, the new pen has one flat edge that prevents the pen from rolling off a table.
The new tips are for me what make it worth buying the new Surface Pen because I write a lot. You get four tips ranging from the least friction (2H) to the most friction (B). The HB tip provides a "medium" degree of friction, and is what ships in the pen, while you get another with the tip set.
The tips come in a holder, color coded and labeled. One end of the holder is the tip extraction tool, it is simply a wide plastic tweezer in which you insert the installed pen tip, press to squeeze the two sides and pull out the pen; the tip remains in the tweezer's grip.
I tested all of the tips, and I think the 2H tip, which has the least amount of friction, is most comparable to the original Surface Pen. When you use the 2H tip the pen easily slides along the screen and feels like you are writing on glass, which of course is what you are doing. To me a 2H tip feels like a rollerball or fine ballpoint pen.
The HB and B (medium friction and most friction) tips feel more like a felt tip pen, and I haven't really decided which I like better. While I clearly feel the difference between 2H and HB tips, I don't feel much difference between HB and B. For now I will use the HB tip.
I did not think that the flat side on the new Surface Pen would make much difference, but I have found that it makes writing more comfortable. Place your index finger on the bottom of the flat edge and you will find the pen more comfortable to hold than placing your index finger on the round portion of the pen.
The original Surface Pen is completely round and has two buttons on one side, one to erase and the other to select. To erase something you press and hold the lower button while scribbling over what you are erasing. With the new Surface Pen, you flip the pen over and glide the "eraser," which is the top button, over the area on the screen you want to erase. One can debate whether flipping the pen over or pressing and holding an eraser button is faster.
The new Surface Pen does have a select button but it is not obvious. Along 90% of the flat side is a raised area that appears to simply provide padding, but you can press in the lowest portion of that pad, which is the select button. If you place your index finger on the lowest part of the flat side (nearest the tip), you slide your index finger slightly up to use the select button.
People who do not use the Pen to write a lot on their Surface will not find the $59 price worth appealing, and I expect most people who already own a pen may not want to pay that much for a replacement. I did find that you can pair multiple pens to a Surface, so I can leave one on my desk in case I lose or forget the one I normally use.
The new Surface Pen comes in three colors, silver, black, and blue, and can be bought at the Microsoft Store. If you write a lot using OneNote, I think you will find the new tips provide a better writing experience.