Okay, I've been lurking about this site for a while and thought it was time to jump in.
I've been using PDA's since the Palm 3e and my x3i is my fourth after my Ipaq got run over. . .yeah, long story.
I've become used to a holster style of case so I was looking specifically for that. I also need a belt clip that will "lock" onto my belt - the stock holster case will actually rotate off my belt as I get in and out of my truck, get under tables and desks (I do computer work in addition to other things), etc. Even though I like it, it was just not sufficient and it really worried me.
So, I read the reviews posted on Aximsite among other places and just looked around.
The general case review on Aximsite had a VERY nice list that I used to look through things and found the NutShell. It had the things I wanted:
Holster
Top flap (this is important to me as I'll explain in a bit)
VERY robust belt clip
Nice leather construction.
Unfortunately, it's expensive - with no extras, it's $39.95. Add a top flap (instead of the little tab) and it's an extra $10. Add a pocket and it's another $10.00.
Shipping was expensive too - either $10.00 or $34.95 for 2nd day. Once I realized it was coming from New Zealand, I thought it was more reasonable. Since it was coming from NZ, I thought I should prolly get the 2nd day air so I would get it THIS MONTH (I've heard horror stories. . .

)
Okay - EIGHTY FIVE dollars later, my case is in. . .and it's sweet!
The leather is very nice. No blemishes, very nice quality.
The fit is EXCELLENT. It slides in with very little resistance - but nicely snug.
The top flap covers the entire top of the Axim. There's no cutout for the antennae, but that's no big deal, it fits fine. It also covers the stylus which has always had a tendency to shake itself loose with me (like I said, I'm hard on things. . .) so I don't worry about the little bugger coming out.
The belt clip is AWESOME. . . It's actually HARD to get the case off my belt!!! YES! The Axim slides right out, easily, but once it's in the holster, it isn't going anywhere.
The case is nicely padded in the right places and reinforced along the back. It's very comfortable (I don't even notice it) and convenient. It doesn't add any bulk to my Axim and very little bulk to my belt.
out of 10 - I give it a 9 - only detriment is the cost!