Rotary Cutters: Are they all they're hyped up to be?

You guys, am I the only stitcher on the planet who doesn't use a rotary cutter? Are they really all they're hyped up to be?
Admittedly, I bought the one pictured above for £1 for some DIY reason I no longer recall. Unsurprisingly, when I tried it out on a sewing project it didn't glide and I had to go over my fabric multiple times...which resulted in a shredded mess. Ever since, I've been suspicious of all rotary cutters and dubious about the value they add. But lately I've been finding cutting with shears more cumbersome that usual, as well as inaccurate at times, so I'm finally feeling ready to branch out!
I could definitely do with your expertise to help me on my way though, like:

• Where can I get a good quality rotary cutter from?
• Are there any particular brands I should look out for?
• Can rotary cutters be used on any type of fabric?
• Are they particularly good for certain types of fabric?
• Is there any scenario where the traditional shears still trump a rotary cutter?
• Do you have any general tips and advice for using a rotary cutter?

I'm looking forward to your pearls of wisdom...thank you!