Good, but not perfect.
This was my first vertical mouse, and I'd tried out a few in the shops to compare angles, and this angle seemed to be one of the most versatile.
I've practically got used to this new tilt during the day (I still make a few unintentional slips and slides after 3 weeks, but nothing I can't handle).
It's really comfortable and I should have taken the plunge a lot sooner!
In terms of precision, the Speedlink mouse is fine (although it often froze the first few days, which was completely unbearable, but after uninstalling my old driver everything finally went back to normal).
The lights are easy to customise.
The materials are of good quality.
Clicks are quiet. In terms of overall design, we're pretty good.
One small surprise, however, is the USB dongle, which is surprisingly smaller than the opening under the mouse, so inserting it has no effect other than to see it fall out the next moment...
This detail could easily have been corrected with magnetic material, I imagine. So be careful not to lose it.
Size-wise, it's just perfect for my big hand! So watch out for very small hands (my partner's left index finger tends to be positioned on the right button).
Otherwise, it's a wireless, perfectly compatible with my PC without the need to install anything.
I contacted the manufacturers to see if this was normal, and they gave me 30 to 60 hours of autonomy. I clearly don't think I've got it... so I've always got a cable lying around on my desk just in case...
In short, it's far from catastrophic, but it's not a revelation either.
I don't regret my purchase, but I think slightly cheaper mice could do just as well.