I had been wanting to get one of these for several years but never pulled the trigger because there were always "safer" things to buy.
I finally ordered one not long ago and ended up returning it. It's a very good pedal, build quality and sound were second-to-none and nothing really does what it does. I just wasn't really sure how to use it and so I couldn't justify keeping it.
It's definitely a pedal you have to learn how to use, which I wasn't really willing to do. It can be as subtle or extreme as you want, but it takes experimentation to understand how the controls interact with each other and how the different loop modes work. It's very easy to get weird sounds out of it, it's more difficult to use it musically. It can do a basic reverse that sits very low in the mix, it can do pitch shifting, and even a nice chorus. In my opinion, that's not what the pedal is for because there are others that can get those sounds more easily and arguably better sounding.
To me, this is more of a pedal that you use as part of a composition. When you start using the looper functions, it can become a delay (with other weirdness added to it), or create very cool soundscapes, drones and glitchy blips and bloops. And if you add an expression pedal, that gives you even more options to get creative.
I never tried a Strymon Deco, but it seems to be the same type of pedal that's not really a specific effect on its own, but almost an instrument of its own that you have to actively play. For my playing and setup, that just doesn't really work for me. I like to 'set and forget' so I can focus on playing. If I would do that with this pedal, I would feel like I'm not using it to its full potential. As such, I would rather have separate pedals for chorus, reverse, delay, etc. instead of constantly changing settings on the Tensor to get those different sounds.
I realize these are all problems with me and not with the pedal, which is why I'm still giving it a high rating. It's an amazing pedal, just not right for me. I was a bit sad to return it because I had high hopes for it, but I had to be honest with myself that I probably wouldn't use it as much as I would have to, in order to justify the cost.
As always, Thomann's service was excellent. I almost never return products so I wasn't 100% sure how it worked, but their assistance and fast response to my e-mails was great and made it very easy.