I have been looking at the Exovault site for the last 6 months or so and had a little email correspondence with them, they do get back to you in a timely manner, Big +. I just really like the case, just haven't convinced the wife it would be ok for me to buy it. Looking back now I should have ordered right after I got my iP4. I would have it and could give a real review instead of spouting what the website claims. As for the screws I believe they are hex, that is how the older 3G cases were secured.
They do respond in a resonable time... Here is some of the info I got from them:
1. The screws we use are 1/4 inch long hex heads counter sunk bolts made from 18-8 stainless steel. These do use an allen wrench (and we do provide one, though any hardware or bike store will also have the right key for the case screws. they use 2-56 threading so you can always replace them with some of your own preference. We use these rather than Phillips bits to avoid stripping the screw heads out.
2. The magnets we use are 1/8" by 1/8" cylynder magnets rated N52. They have about a 5 lb pull. so even when we do drop a case on the concrete floor of the shop here they stay closed.
3. The hinges are steel pins. If you are worried about durability might i suggest the screw shut version? that makes for a solid case, and if you plan on using a screen protector its the right choice. We machine these to extremely tight tolerances and the hinge case wont always close properly if a screen protector is present.
4. Outside dimensions for the case are as follows: 118.13mm tall X 61.41mm wide X 12.19mm deep
5. We do receive some complaints about signal degradation when using the case, this is to be expected with any metal case. It mostly depends on the quality of the network where yo are using it. We work in a basement in east broklyn and have no problems among the 5 iPhones here, other people have had issues inside thin frame houses. YMMV
6. We have a very generous return policy, though we do reserve the right to limits returns. We accept cases in like-new condition within a reasonable time of purchase and issue a full refund for the case. We can provide free replacements if a case has a defect, either a poor fit or a manufacturing flaw. And we provide repairs for a nominal fee for the life of the product. You can find a copy of our return form by searching for "exovault return"
7. We cannot guarantee the fit of third party connectors (now why those companies give these outside shapes to the connectors is beyond me)