S2 sound quality

Hello colleagues. I need your expertise on my latest issue.

I've been using Traktor together with a Numark Mixtrack Pro for almost a decade now. Generally speaking, I've been happy. However it has recently come to my attention (in a specific place I've recently played) that the sound quality of my controller is not what I would expect, when it comes to big sound volume and dynamic range.
In particular, I've been playing to a place that has a whole different infrastructure on site. CDJ1000s (which are actually used as jogs and buttons only), NI Audio 8, A&H mixer. Also plays with Traktor. Obviously the sound produced by Audio 8 is way much better (although I also connect to the same mixer). This is not easily noticed until late when the volume goes high. My sound looks distorted and especially the low frequencies are way much better with Audio 8.

At first: Am I right? Meaning, does the above case sound 'expected' to most of you?

So I've decided it's time to upgrade. I lean towards S2 MK3. I am what you might say 'old school DJ', and I do not really use features like samples, pads, effects etc. All I need is the best possible sound quality. So my questions are:

1. Would I be able to achieve the same result in terms of quality with S2 MK3 as in Audio 8?
2. Should I go towards something like Pioneer DDJ-SB2 instead?
3. Generally which model would you recommend to my needs if the above dont fit?

Thank you I would appreciate some response.