IMHO, UI is a kind of irrelevant subject, a simple matter of personal taste.
However, a minimalist UI, with processes and mechanisms that are not clear, that might be a problem.
The ZA webpage is not bad, but I find it incomplete (many explanations and details are missing). I also find ZA webpage confusing in many aspects, including its product names and links (I found several inconsistencies).
And when there is no information or details about the processes/mechanisms, then the minimalist UI may generate a feeling of "I don't know what's going on". And as it was well mentioned in this thread, ZA ends up forcing the user to trust and believe in what the user doesn't see, doesn't know, doesn't understand.
Just by adding few details and explanations in ZA webpage, may solve lot of these possible user feelings.
But more important, adding few new functions to the minimalist UI, also will help a lot. For example: Basic app controls, Basic Firewall granularity, Basic Antivirus behavior (not deleting files etc), Privacy options, Browser extension/add-on option, General ON/OFF switch or an exit option... and so on.
PS: As I read in this thread, it seems that current ZA will have more functions incorporated to the present UI. One possible scenario is that the ZA merger with Check Point led to the release of a first model, which soon will be expanded and improved. Perhaps current ZA is just a work in progress, the beginning of a great product now under development.
The RAM, yeah, ZA eats a lot (around ±1GB in passive mode). However, if you have more than 8GB RAM, then ZA is not a problem because eats lot of RAM but without impacting CPU, disk I/O etc. Personally, I have plenty of RAM, and I don't feel any negative ZA hardware performance. I found several antivirus/anti-malware consuming small amount of RAM while killing CPU and I/O. I prefer ZA.
The first scan time, is irrelevant... depends on the amount of files on disk. Users with few files on disk, will have a fast first scan. And vice-versa, my first scan took time because I have lot of stuff in my disks.
Another positive ZA feedback to mention is "the silence". Yeah, ZA will popup a message/notification only when really is needed.
And ZA is clean of bloatware.
Also, I never saw a single message trying to selling me something or offering me upgrades, nothing... clean and silent!
With regards to the cons, so far I found three:
1. The automatic browser extension/add-on installation is not solved just by turning off that function.
I totally understand the benefit of ZA extension/add-on. But 90% of my software (including browsers) are portable. So, I don't want non-portable software installing stuff in my portable software.
And as I said, unfortunately the "off" option at Web Secure is not solving the issue.
2. ZA keylogger function messed up my keyboard. Probably because my keyboard is configured to be able to use multiple languages. I don't know. The point is that the problem was so big, that I had to uninstall ZA, I couldn't use my keyboard anymore. Even disabling the keylogger in the UI, the problem persisted. Once the keylogger function is activated, the problem appears and is solved only by uninstalling ZA.
3. When uninstalling, ZA leaves lot of folders on the computer, and worse, it leaves lot of traces in the registry. That happens even using a third-party uninstaller. The ZA uninstall process is quite messy or dirty.
But please let me be clear, none of the above is really important. There is no perfect software. All software has pros and cons.
Since ZA hardware performance can be solved with more RAM, then the only issue that really matters is ZA protection. If ZA's protection capabilities are confirmed, all the rest (UI, webpage, confuse info, dirty uninstallation etc), IMHO will be irrelevant.
For me, the key point with regards to ZA, is to confirm its protection capabilities.