Received the khaki Ion 4 this evening. No pictures yet but I'm working on it. In the meantime I'll give some preliminary thoughts.
The TPU polymer material is flexible enough to allow you to work the case onto the phone but at the same time stiff enough that once it's on, I don't think you'll have to worry about it becoming loose. I should preface my comments about putting the case on by saying that my phone currently has an SGP crystal back protector, Ultra Optics screen shield, and Lucky Labs spectra wraps so YMMV. The installation was not particularly easy for me because once I slid the bottom of the phone in, the top two corners were hard to manipulate onto the phone without possibly wrecking the spectra wraps or the screen shield (at least I thought I might wreck them if I forced the case). In any event, this is not a case that I would want to take off and put back on frequently.
With the case on the phone, it has a good feel thanks to the textured sides and I would have no worries about damage to the phone if dropped. I quite like the look of the case, especially the backplate. The case comes over the sides of the phone so there is the ability to lay it with the screen facing down. That being said, the case hugs the phone tightly enough that it has bubbled my screen shield slightly in a couple of places. Like I said before though, YMMV depending on whether you have front and back protectors, etc.
The camera opening is a good size and shouldn't cause problems with the flash. The cutout for the 30-pin connector is nice and big and it isn't too deep so you might be able to use some docks (I have none so I can't confirm this). And the cutout for the volume buttons is good and allows for easy access. Ditto for the headphone jack and on/off button.
Overall this is a good case however I don't believe it justifies the $60 (plus exorbitant shipping) price tag. The biggest negatives are that it wasn't easy to install (maybe due to my other accessories) and it's bubbling my screen shield. However, it's a smart looking case and will provide good drop protection. Hopefully I'll be able to post up some pictures soon.