fizzie, you're talking about the Seidio holster, not the Wireless Galaxy holster, right?
The bottom part of the Seidio holster more than adequately holds the phone, even with the Start/OK mods in my Seidio review. The real problem is the tab accidentally opening, as you indicated. Since the incident in my review, I have had 2 more accidental pop outs. One of them knocked my Kaiser completely out and it fell to floor. Fortunately, the floor was only a few inches away because I was under my desk messing with wires at the time. Whew!
And this whole accidental opening thing is what's so funny about all the face-in advocates (including Seidio themselves) who are opposed to my ideas of making the Seidio holster reversible. They're so obsessed with face-in protecting the screen that they refuse to even acknowledge that a few minor design changes could make the Seidio holster fully reversible. I guess the very idea of using the Seidio holster face-out is sacrilegious to them. Yet if they really want protection, they shouldn't be using a holster! I mean, let's face it, whatever could potentially press/scrape against the screen could just as easily press/scrape against the holster's tab and send the phone crashing to the floor, which would be far more damaging than a little scratch on the screen. Plus there's the wear and tear you mentioned because over half the phone is exposed.
In contrast, a leather pouch offers much better protection without the risk of accidental popout. But with leather pouches I end up accidentally pressing buttons when I'm fumbling to pull out my phone and inevitably send important calls straight to voicemail. With a holster, I don't have that problem. Plus the holster is faster on the draw--even faster than the releasable clip found on some leather/metal cases.
So ultimately what you're really getting with a holster is not protection, but convenience. Say, you know what would be really convenient? A face-out holster! Oh, great...here comes the face-in zealots with their "Face-in protects the screen" mantra. (In all fairness, I have to reiterate from other posts that most of the time I use my Seidio holster face-in to protect my screen, too, but also like to flip my phone face-out for accessibility.)
I came to ATT from the nextel world and face-in is how all their holsters work... I like the face in idea, especially because the speaker is on the back of the phone, so it would be easier to hear with a screen in clip... I went to FRY's last night, not a single viable option for a holster... I'll have to keep looking around