I use the
S Pen with the holder and find it infinitely better than the stock MS pen.
I has a better weight and feel to it and it is easier to write neatly and for a longer period of time - due to the shape, weight and softer rubber grip.
It doesn't have an eraser though. But, I haven't missed it. I find it quicker to use CTRL-Z or tap the undo button when writing or drawing.
It also seems like the sensor is closer to the tip than the MS pen because there is less variation in accuracy as the change the angle of the pen. Eg. hold the S Pen at 90 degrees and the cursor touches the tip, hold it at 45 degrees and it is still almost touching the tip. Hold the MS Pen at 90 degrees and the cursor touches the tip, hold the MS pen at 45 degrees and the cursor is further away from the tip.
It says $60 on the Samsung site, but I've seen them for $30 on
ebay.
I got mine from a Samsung shop here in Thailand for 900baht, which is about $30.