EVFs cost far too much money, and unfortunately people think they're getting value with something like this product. I ordered two. The first one died within moments of connecting to my camera. Amazon quickly dispatched a replacement.
The replacement (and the original for the brief moment it worked) were not sharp. Even with the diopter adjustment it always seemed as if the LCD panel was not quite sharp. I appreciate function buttons, and they are mostly useful...but...the implementation is a bit cumbersome. The peaking function, for example, is far too aggressive. It's not possible to make fine-tune changes since this EVF seems to think everything is in focus at a particular distance--and when you compare with the camera's peaking function, there's a clear difference. The camera has a more accurate rendition of what's in focus.
The eyecup is a real pain. I see the benefit of not having a giant eyecup of the type that Zacuto uses, but the one included with this product is just too flimsy and uncomfortable. When you adjust the diopter, for example, the eyecup also moves and shifts. And, my eyecup's cover constantly pops out of place.
There's also a small, tiny particle between the LCD and magnification lens. As you might imagine, the particle is also magnified, and blots out a small, but annoying, amount of of the LCD. No amount of tapping on the EVF has been able to dislodge the particle. You can't unscrew the magnification lens to access the LCD itself--it's an all-in-one unit. Unfortunately, the first EVF I got also had a similar small particle issue.
Updating the firmware on this EVF was a struggle. I followed the instructions but the EVF wouldn't update. The instructions are also incomplete. When you download the firmware package, there are multiple files, and ALL of them need to be present on your USB drive--but the instructions don't make that abundantly clear. I reached out to customer service at Portkeys. To their credit, they responded within 24 hours and told me to try a different USB thumb drive, and keep trying to force an update. Eventually it did work--but it took far longer than necessary.
Clearly this product could be a real bargain--but it isn't in this condition. There's a noticeable lack of QC. The software is not quite as useful as the marketing suggests. The inability to dial in peaking sensitivity is a huge issue for me. I'll keep the EVF as it is more useable than the Sigma EVF-11 for my fp, but that's not saying much.
This was a pretty big disappointment for me. Maybe someday Portkeys will release a far better version of this, but until then I can't recommend it.