That is always a hard question to answer, because no one knows exactly what new "un-hackable" model may have just been introduced into the supply chain. But the ones people have reported receiving in recent days with the 2.3.X firmware are still partly hackable. In particular there is still a resolution hack available to get to the E8 resolution, but what is still missing is some of the extended menu functionality of the E8, so in effect the current hack gets you a higher resolution E4, and some of the recent sub-hacks that get some of the extended menu functions back, but not yet all of them. As to the difficulty of performing the hack, overall it is what I would call a mid level skill hack, as they have introduced a few obstacles that makes the process a bit more complex, but once you determine what it is you need to do for your particular revision the process only takes a few minutes. I just did it for the first time yesterday on a used E4 which had the latest software, but slightly older firmware which added some minor complications. I spent about 3 or 4 hours reading through old messages in this thread, determining what I had, downloaded various bits of software, had to trouble shoot some of the installation, go out and dig up a driver to download, etc. Much of this time was spent due to the high level that the instructions are written at, such as "put E4 in RNDIS mode", so go spend 45 minutes finding out what RNDIS mode is and how to set it, find that there was a hidden menu for RNDIS on older firmware models, but newer ones needed another way to trick into RNDIS......