Well I can tell you what else I know since posting this... not much. hehe. No seriously, I haven't been busting my butt researching these, I don't even have a DVI LCD yet, but I have occassionally looked to see what people are saying about them.
IOGear seems to be a great choice, UNLESS you are going with an NForce3/4 motherboard, which is exactly what I have been looking at. The IOGear KVMs have upgradable firmware, but this issue has been known for a LONG time and IOGear has pretty much blamed the problem on nVidia and doesn't appear to be concerned with fixing the problem themselves and upgrading the firmware. Apparently there has not been any firmware releases since this product has been out, which has been many months. Makes me wonder why they even bothered listing it as an option...
Avocent is well known in the server KVM market. They're known for quality and often times other companies (such as Dell) take their products and rebrand them with their own logos. I have not been able to find ANY reviews of that Avocent KVM i mentioned above. NONE at all. It's not even sold on Newegg. *rollseyes* HOWEVER I have noticed on Newegg DVI KVMs by "Linkskey" which look nearly identical to the Avocent ones. In fact I'd be 95% confident in saying that they are rebranded Avocent KVMs. And those DO have reviews on Newegg, and just like with all the other KVMs, they aren't good. I am hopefull though that the actual Avocent KVMs utilize some better firmware or components that make their product work better, which LINKSKEY took out to save costs. But that's just hopeful wishing probably.
The ONLY conclusion I have been able to draw, is that these KVI+USB KVMs are "Hit&Miss" on whether or not they'll work with your computer, keyboard/mouse, and monitor correctly. It's a pretty sad state of affairs. You think it wouldn't be that difficult to actually make a good product, or to even offer a list of known compatability issues with a product. KVMs will forever remain the most overlooked unessential (but very beneficial when they work) peice of computer equipment at this rate.