For which specific applications or uses have you chosen this product?
For small performances and home use.
How long have you been using it?
I've owned the SX1 starting June 2014, then the SX2 since February '15
Have you tested other comparable or competing products before purchasing this one?
No other controllers, but just before I had a CDJ 1000 + DJM 700.
What are the pros and cons of this product?
Pros: easy to transport, intuitive and easy to use (except for Serato Flip but I think it's because I don't use it enough...), does what it's expected to do.
Cons: I had CDJ1000s before the SX, which I bought for transportation purpose since my live use didn't require so much, but I have a lot of regrets. The jog is too small for me, even if I don't scratch much (I love to but it's not made for it! ). The controller feels like a toy at first sight (that's just my opinion), effects are not bad but it's still better on an external hardware - not with a software.
Frankly, the controller is perfect for mobile DJs who have to transport all their gear every weekend, as it's light and easy to transport (especially with the DJC-SC5 bag). But, if you like to mix/scratch and develop your creativity "as much as can be", this won't do for you.
So, all CDJ1000/2000 or SL1200 (or any other turntable, by the way) owners should think twice and skip this one, there's no enjoyment to expect from it (except the moment you put it back in its bag at the end of the evening ).
Otherwise, the concept is not bad but it won't replace a CDJ/SL1200 + mixer setting.
Yet, it's a good start for beginners.