I have not bought but I tried and this is an amazing controller. Something that I feel Denon should change for the Prime 5 or whatever is going to be called, is the effects section. I think just like X1850 the effects should be next to the EQ section.
Also are there any rumors about when the next PRIME is going to be come out?
I bought it. It is a good controller but the effects are useless. They are really weak comparing to Pioneer or even comparing them to DJay APP like all the APP of Algoridim. They need to improve them in the next update. Neural system in the new update of Algoridim is great. Denon should work on that too.
I think the FX should be chosen by a knob as in pioneer, not a sequential button! Big big issue which you will only know as a DJ.
Many people here do think that the Denon effects were chosen by a knob 
[sorry]
Maybe you have a different Prime 4, because the effects on mine are selected with a rotary knob.
My suggested improvement would be the ability to re-order the effects and/or deselect any you don’t use, so you don’t have to scroll through ALL the effects.
lol
yes I forgot mine are chosen the same way. But it is a tedious workflow compared to pioneer and difficult to choose instantly. Especially when you cannot save the defaults. They take alot of time to setup.
They should have asked a DJ about this area because it is so off the mark it is obvious they did not.
Hopefully in the next update… 
I fully understand what you mean: you would like a “click” rotary knob so that you can immediately set the desired effect. Instead on the Prime 4 you have to turn the knob (encoder) and read on the display which effect you have selected. You’re right, i know.
However, we can say that in the way used by the Prime 4 there is the advantage that (in theory) they could add new effects with different names, increasing the number of effects available without having to change the knob or the silkscreen on the console.
This is also true. There were also requests to be able to save the settings for each effect, so that when you select it with the rotary knob you can already have everything set. However, like many other requests, they remained written but not fulfilled.
If it is useful to you, I use the two FX banks in this way: I do not tie exclusively the FX on the right with the decks on the right and vice versa, but I use the FX according to what I have to do. For example I keep an effect on FX 1 to be used during the transition of a track (Echo, Hall Echo, Roll, etc.), always set with the necessary parameters; instead on FX 2 I keep an effect set to be used while listening to the track (Flanger, Phaser, Beat break, etc.) also with the settings that I consider useful. Then I decide how to combine them with the various decks, so it can happen to use deck 2 with either FX 1 or FX 2 depending on the moment I think is appropriate. So you take advantage of having two separate FX banks, which is not possible with Pioneer.
As someone who has never used Pioneer, I don’t find the effects section problematic. It’s all a matter of getting familiar with it. When you get used to one way of doing things, a new way is always hard. Now if you were to hand me a Pioneer controller, I’d be fumbling around like a monkey with a typewriter.
We cannot overlook the fact that actually selecting an effect with a Pioneer console is faster than on the Prime 4: on Pioneer you rotate the selector (click … click … click) and in half a second you are on desired effect. Instead we must read the text on the OLED display and continue to turn the knob until the desired effect is achieved.
But with the trick I explained above, we can take advantage of our double FX bank.
True, but all the equipment I’ve been using lately (MPC, digital mixers, Prime 4, etc.) all use rotary encoders. Not saying it’s better, but I’m able to use it just fine. I can see how the Pioneer knob would be faster, but having all the rotary encoders to adjust the effects and parameters is what I’m used to.
One question. Is it possible to keep the effects on when we are changing from one effect to another? It goes to off position automatically.
Thank you
As some of the effects on the prime 4 aren’t the best I always wonder whether you could change them and put on new effects from you computer like spiral etc?? Someone get back to me thank you
Hello @Richard_Roberts Welcome to the forum.
No custom FX can be added from a computer. Only fx change/add can be done by Denon in a firmware update.