Sorry for the bump.
I'm trying to buy some new 5.25 floppy disks.
They are brand new and still sealed, they are sold for the same price, can you tell me which is better between those floppies?

They also sell those unbranded floppy for a lower price:

What would you buy?

Verbatim Verex are the cheaper offering vs their DataLife (+) series. Not saying these are trash, far from it, but surely the lower price was enabled by something (materials, manufacture).
The last box is some generic no-names, and only 77-track ones (so this looks to be for some JP computers?). Just because it says 77 tracks doesn't mean it won't work with 80 but at least they are marked as such. Could be simply the magnetic material is not so great and the last tracks are difficult to write/read so they'd rather sell it as 77-track.

I know little about JP floppies, never really had them in any quantity to tell how good/bad they are. But both Fuji and Sony knew how to make floppies. In fact I find the mention of a hub ring on the HD Fuji floppies quite intriguing - I'd buy them just to find out how that looks and works.

I'd avoid these specific Verbatim Verex disks (but not others), based on the statistically inaccurate sample of... one case. Have a look at this post, my experience with them was not so good: Re: Floppy disk quality.

Thank you for the answers, so the not branded one are off, verbatim are off, I thought to take the Fuji too.
The 77 tracks means that they have less than 1.2mb space available?

I've recently bought sealed box of "Boeder" brand (it's German brand and I guess not very famous) - I have no idea if they are new-old-stock or recently manufactured, but they are "made in Germany" (probably rebranded and from some major German company like BASF most likely) - see the attached picture for reference, even though "Boeder" have many different box designs of their 5.25" floppies. So, of those 10 diskettes out-of-the-box:

* 2 were full of bad sectors (something like over 50%), I trashed them right away
* 3 have exactly 7KB of bad sectors , but they are stable, i.e. the number doesn't increase after I read/write/format them many times
* 5 are just perfect, no bad sectors and I am using them in the last few months, they still continue to be bad-sector-free after many read/writes/formats

I consider that as good deal, because I paid 15 bucks for that box of them and got 5 perfect diskettes and 3 usable.

Nemo1985 wrote on 2023-02-27, 12:57:

The 77 tracks means that they have less than 1.2mb space available?

Space is defined by the format - though obviously the media material, quality and drive heads put an upper limit on what can be reliably recorded. 1.2MiB is just a standard among others, you could just as easily use another format: 1-sided for example, or put more sectors and less space between them like what FDFORMAT does to put 1.44MiB on 5.25" floppies.

IBM PC uses 15 sectors of 512 bytes per track, 80 tracks, 2 sides = 1228800 bytes. Some JP systems use 8 sectors of 1024 bytes per track, 77 tracks, 2 sides = 1261568 bytes. It's actually more space, and the simple answer would be "no, it doesn't have less than 1.2MB space available" but it's not that simple. Just FYI this is not a PC-compatible format and PC can't read such disks anyway because of different rotation speed (360 vs 300 rpm). Well unless you have hardware (3-mode capable FDC and drive) and software to support it.

A word of caution: Floppies marked as "77-track" one could have shorter cutout/window in the envelope for the heads to move in. It's rare (like a true 1-sided media), most have standard 80-track cutout, but there are exceptions.

I see thank you very much for clarification, I will go for Fujifilm floppies.

mattw wrote on 2023-02-27, 13:47:

* 2 were full of bad sectors (something like over 50%), I trashed them right away

De-magnetize your floppies and format again. Retry a few times. Surface cleaning can help too. I've brought back many "dead" floppies that way, including ones with stains, mold (removed of course), and deep grooves made by dirty 1-head drives. Some disks I have most people would toss in the bin just by looking at them, and they are quite reliable in clean, cared-for drives.

Deunan wrote on 2023-02-27, 14:04:

mattw wrote on 2023-02-27, 13:47:

* 2 were full of bad sectors (something like over 50%), I trashed them right away

De-magnetize your floppies and format again. Retry a few times. Surface cleaning can help too. I've brought back many "dead" floppies that way, including ones with stains, mold (removed of course), and deep grooves made by dirty 1-head drives. Some disks I have most people would toss in the bin just by looking at them, and they are quite reliable in clean, cared-for drives.

Sorry to bother, since you seem quite expert, what do you think of such thing?
Re: Amstrad 5.25 floppy drive compatible with 386?

Nemo1985 wrote on 2023-02-27, 14:13:

Sorry to bother, since you seem quite expert, what do you think of such thing?
Re: Amstrad 5.25 floppy drive compatible with 386?

I wouldn't call myself an expert, I just have some experience with old floppies and drives - other people might offer a better advice. I've replied in the thread you linked.