I've been using it without problems for many years. About 3-4 months ago, scripts started to be deleted when syncing, I was shocked! I added several accounts to save the scripts, and noticed that after a while many of the scripts disappeared.
It's good that I had a backup, because I have almost 200 scripts (but half are disabled now). And so it would be... It would be a disaster to lose everything over the years. In short, after synchronization, the program deleted most of the scripts and left 20-30 pieces. I figured out how to delete the sync and saved it manually.
Now, about 2 months ago, new problems started. Scripts stopped working on different sites, from YouTube to others. And most importantly, you don't even think about it. I noticed that the functionality on YouTube is missing. And only then did I notice that the script manager had fallen off there and was no longer working on YouTube, the icon was not glowing on YouTube.
Now new problems have begun. And I also didn't think about the script manager, but I thought about the scripts themselves, that they didn't work. But it turned out to be him.
I turned on Tampermonkey and everything worked. Before the latest updates, everything worked fine for years, so you don't even think about the script manager.

Zero privacy. Collecting your data, sharing with unknown 3rd parties. Unacceptable.

Not working. POS.

had to finally switch to tampermonkey. i migrated from greasemonkey following the user script breakage after their 4th version update, now it seems that violentmonkey followed suit, resulting in many scripts not functioning anymore.
also their privacy statement gave me the creeps..

Privacy nightmare. Avoid like the plague if you are privacy concious.

安卓下好像没有用

They are collecting "certain personally identifiable information" and moreover:
"We may employ third party companies and individuals to facilitate our Service, to provide the Service on our behalf, to perform Service-related services or to assist us in analyzing how our Service is used."

This kind of behaviour is unacceptable for any privacy conscious person. If you want to collect any user data you should make it opt-in. Most Firefox users care about their privacy - that's the prime reason they use it.

2.9.8 completely broken, even Dashboard doesn't open, no scripts show as installed or are used. Have Waterfox 64-bit, but seems it affects Firefox users too.