I have owned and shot both of those plungers in competition for the last 5 years or so. So I have a fairly decent idea of what they are like.
The SecurClick (I think that's its name, the one without the red button) is effectively a Beiter clone. I'd even consider it a bit of an improvement, since it doesn't have a barrel with two thread sizes that Beiter uses for a reason no one has been able to explain to me. Ultimately, though, it is functionally identical in design. The machining is not quite as good, though, and it does not come with nearly as many accessories. But it is also noticeably cheaper to reflect that, and it still shoots just fine.
The SecurButton is what I currently use. In terms of its design, it is strictly superior to the ubiquitous Beiter. It's completely tool-less and effectively impossible to move without intending to move it. I actually often just remove the red button, since it just threads out. An X10 point is the perfect size to stick into the hole, activate the mechanism, and make any adjustments necessary on the line. And its price is usually either equal to or lower than the Beiter.
The one big caveat, though, is that their machining quality seems to be deteriorating. I have an old SecurButton that my coach passed down to me that still works beautifully, but the new one I bought about two years ago would not fit properly into most risers I found until I used a die to thin down the threads a bit. It's quite a shame, since i honestly think their design is really good, but it's just let down by weird tolerances.
As for tips unscrewing, I have never had that happen once in all of my shooting. Quite anecdotal, but it's never been a concern. Worst case scenario I'd just use a light glue on the tip if I was that concerned about it, but I've worn down tips completely without them showing any sign of coming loose (which made them very annoying to remove).
Feel free to post any further questions.