I have used the Fold3 for about two days so far after receiving it on launch day. To me, it lives up to the hype.
POSITIVES
The device itself feels sturdier than the Fold2 I used to have. The difference in materials used for the Armor Aluminum casing is noticeable. Its appearance is more refined as well, with a beautiful finish on the silver model and a slimmer, rounded camera array compared to the blocky array on the Fold2. The Addition of IPX8 is fantastic and quite a feat for a third-generation foldable device. This week was the first time where I brought my foldable outside in the rain and had no worries about it.
The main display is noticeably brighter on the Fold3 due to changes in the display technology. Colors are brilliant as well. The biggest improvement here is that the crease has almost completely disappeared! I have been using the S Pen Fold Edition heavily and can't tell the crease is there when I glide the Pen across it. Though it is still visible at different angles, it is less noticeable and allows better immersion with the main display. The cover display now features adaptive refresh up to 120 Hz just like the main display, which elevates the refined feel of the device.
The software upgrades are amazing, to say the least. Having the ability to keep a permanent taskbar on the side; being able to force applications to work with Flex Mode, split view, and pop-up view; and adjusting aspect ratios for individual apps is a godsend on an unconventional productivity-focused device.
I will go against the grain and say that the Under-Display Camera technology is well-implemented on the Fold3. Some reviewers harp on how terrible the pixels look over the camera lens. Unless your eyes will stay fixated on the camera the whole time you use the phone, you will not notice them most of the time. Usually your focus will be on the screen's content; I never notice the UDC pixels in my peripheral vision. To me, the viewing experience is uninterrupted. Besides, how are these pixels any worse than having a permanent black notch on the screen? In addition, the 4MP quality of the UDC is a moot point. Fold3 users will not be taking selfies with the main display because the phone will be too difficult to hold and operate when taking a selfie unfolded. 4MP is the kind of resolution used for video conferencing, which is the type of activity this camera is intended for anyway.
NEGATIVES
This is still an astoundingly expensive phone, easily double the price of other high-end flagships. The price alone is enough to deter casual phone users or users who would otherwise be interested in a productivity device. If you are not a user will be able to fully optimize the phablet experience, then this phone is not a good choice for the money you would be paying. It remains a niche option for power users.
A main downside that immediately comes to mind with this iteration is the S Pen implementation. Some reviews get this detail wrong -- the cover display DOES NOT support S Pen input. There are digitizers only under the main display. There may have been technological or financial limitations that prevented implementation on the cover display with this iteration. I would very much like to see Samsung work on rolling out S Pen support for both displays on the Fold4. Being able to whip out this masterpiece and jot down notes without having to unfold the device would further optimize productivity.
Similar to the S21, the Fold3 does not have a dedicated silo for the S Pen. It also works only with the S Pen Fold Edition and the S Pen Pro due to different frequencies and pen tips. This can be a bummer for Note fans who like the dedicated silo, but this was likely a compromise Samsung made to keep the phone from getting too large (both the S Pen Fold Edition and Pro are thicker than the phone itself). Samsung offers a case that will hold the Fold Edition, but there is no storage option for the Pro.
Case options are limited since the device just launched, but it would be nice to see a good-looking case that holds a Pen AND features a kickstand. This is important to me because my media consumption on the Fold3 is pretty heavy. The S Pen Flip case can kind-of work as a kickstand, but from my experience it is temperamental and depends on the kind of surface you set the phone on (smooth, low-friction surfaces like countertops don't provide enough resistance to keep the case flap from sliding). Some available cases have a kickstand, but as of writing there is precisely one case that can store an S Pen and it is the Flip Case.
Overall, whether this device works for you will depend mainly on how much value you need to get out of your phone. I do not recommend this device for most people simply because most people do not need this level of power and usability out of their phone. For those of you who need a tablet that can double as a phone, the Fold3 is definitely worth considering.