I like to leave ACCURATE reviews about techy stuff, because I personally find the reviews section really helpful for things like that before buying. It's not really about positive/negative though, different people are looking for different things so it's about trying to be detailed, balance of quality vs price etc.
I'll only leave a bad review if something is such absolute trash that it would be objectively a waste of people's time/money to buy it or use that service. e.g. I one-star-panned a USB Bluetooth receiver recently because having tried it on three different PC's, the ****ing thing stutters and cuts out constantly if you try to use it for headphones or speakers. Utterly useless
.
And I only had to buy it in the first place because the dog managed to get hold of (and, thus, eat - if she getses it, she eatses it) the old one which worked perfectly
.
I'd review her if I could. "Very friendly, likes hugs, lots of fun, good with kids and other animals. Will eat ALL OF YOUR STUFF. Three stars
"