New Amp

In the process of upgrading my amp and was looking at the Denon AVR-X2300W

Mainly used for Sky Q, PS4 (Pro when its released) and a Fire 4k

The speakers I have are Canton 75 Movie speakers

The Denon is meant to be nice. What are you upgrading from and why do you need to upgrade? Are there specific features that you need that are lacking? Do you not like the sound?

Its a Onkyo HT-S5305B that I've been using recently.

Following Sky Q being installed I'd be looking for something with hdcp 2.2 support and 4k support plus the current amp doesnt seem to be too strong with the surround speakers

How does the demon amp perform or are there any alternatives

Yamaha sounds better than Denon or Onkyo for the same $ in my opinion and that of my audiophile friend Steve.

It's all rather subjective at this price point. I don't think you'll be getting a massively superior listening experience with one or other brand. You'll struggle to buy a lemon IMO. The denon amps are highly rated, but then again all the other brands have their own following too.