I have a Panache custom stylus for X5. I love the heavier weight and a stronger, slightly rounder, orange tip :way to go: . I haven't used the PPCTechs' one so I can't give you a comparison.
The Panache stylus is not flush with the device. The 4155 stylus might be different. But I like it this way, making it esier to take the stylus in and out. The stylus doesn't sit loose but it doesn't sit tightly secured in its silo either. If I tip the device up-side-down, the stylus is in no danger of falling out. I try to shake it really hard, and it still doesn't fall out. But "shake it really hard" is subjective

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I personally do not want a pen/stylus combo. I am sure I would some day use the wrong tip on the wrong surface. If you are less absent-minded than me, go ahead :wink: .