In my personal (and professional) opinion, these mechanical toys are a waste of cash.
There's far too much that can go wrong, they are not durable and are often made of cheap materials to keep costs low.
They're also usually very noisy, so unless you live in the outback, trying to be subtle while using one is just not possible.
Batteries don't usually last very long.
The most successful toys are based on the silicone sleeve, and the reasons for this are that they're durable, last for years and can offer a whole range of extremely pleasurable sensations with just slight variations in texture.
I don't think I have ever seen a bad review of a silicone toy that you put your dick into. From the basic flexible tight sleeve to the fleshlight, they are appreciated by guys all over the world.
Some of the most recommended toys are simple and basic, and offer great sensations that just will not be achieved by mechanical masturbators...
In my experience, these are some of the most popular toys for wanking, along with the remarkably best selling fleshlight of course.
By all means try a mechanical one. I just think people are sucked in (excuse the pun) by gadgets that look interesting while ignoring the sensations that will be achieved (or not) by such a toy.