it does NOT sync properly between browsers [Firefox - Chrome - Opera]
I have all 3 and use Firefox as my primary browser. I add dials and or delte some on a daily basis. But when I SYNC between Opera and/or Chrome, none of the "Groups" properly reflect the dial count or even the arrangement of groups the way I have them in FF.

If none of those basics sync, then it's actually stupid to even have everhelper installed. Because it does not "really" sync.
Same with bookmarks. That's an entire more horror. IF it ever completes at all, then it decides on its own, to simply "duplicate" the bookmarks.
By now, I have 3 duplications on firefox. It is taking forever to re-organize and delete, because now it never completes any sync for the bookmarks due to a over 150,000 count because of the duplications. I will see to get all my dials properly downloaded [not as json] and hopefully fins a way to import them to chrome via a fresh and clean FVD install in Chrome. I wished they would have kept the original saving sd version.=============================

After some time now, I tried this again.
Have to say, that NIMBUS fixed my firefox.

But I only allow the speed dial, not the bookmarks, because it will take me another 6 months just to properly eliminate all duplicates and re-organize the way I initially hat mine.

Speed dial: in OPERA I can no longer use it because it produces an immediate crash after opening. It's not a surprise though because it tries to either sync [without me having sync enabled] I tried the backup as sd file. It saves it of course from FF, but cannot import it as such to Opera. So, I saved it as text - which I appreciate that this was implemented - and I loaded it in to Opera.

Well, 15 hours later - there was zero imported other than all empty categories. I checked with Taskmanager [win 10] and not surprising it had ovr 60 instances of Opera windows open.

So, I had to scrap this tryout also.

Then I went ahead and installed the Eversync again [I did a clean install of the latest Opera] and it seemed to be working OK.
But - despte that I disabled "autosync" because I have a lot of dials, it says that auto update is disabled now. But this is unfortunately not so. Opera is open, Eversync is open, Speed dials are loaded in after 1:49 hrs. But that was several hours ago, and Opera still syffers with blank dials [url is OK, just nothing else, and it tries to update every single dial at once across all categories.

Taskmanger: Opera holds a steady 18 instances/browser windows - just never finishes even one. I have over 80 groups and checking [using the moment Opera is responding again for a few seconds] and see that it does literally try to update every single dial at once across all groups.

I will minimize the browser and let it run now for a few hours. Will see if it ever finishes at all.

Fact is - definitely NOT for any work environment to be used. Not on Opera. I uninstalled the browser, including FVD and Eversync in the first place because I thought maybe with a clean install Eversync, and or FVD would actually work properly. It imported all Groups [empty] but also nowhere near my arrangement I have in Firefox. Nope it just randomly sorts the groups [no idea where it takes that from]. I am logged in properly - but it makes no difference, Eversync/FVD does whatever it does. Not A proper SYNC.

I understand that a proper SYNC would give me the identical group arrangement on the second browser, asI have it in Firefox.

Firefox is my daily browser and I have the groups and dials arranged exactly the way I need them.

With Eversync, if lucky to get anything at all after hours, all I encounter is a total mixed up group arrangement and definitely not my latest dials the way I have it in Firefox.
So - bottom line: Uninstall the extensions from Opera because with them enabled I cannot use Opera at all.

If Eversync is disabled, then the browser functions a little better. With both - FVD and Eversync disabled, Opera speeds and exceeds even Firefox and Chrome.

So, it has little to do which browser you use, if you have more dials than the average, prepare yourself for molasses.