That is very, very impressive for a mere 40 minutes of exposure.
Your colouring is informative are very much spot-on. Compared to, for example,
Bert's recent M8 (and many other M8s on this forum) you managed to keep color constant and comparable regardless of where a pixel sits in the dynamic range (e.g. you took your luminance processing out of the equation where possible). Consequently, you have extensive coloured detail in, for example, M8's core, which gives the observer clues about its chemical make up and/or other processes going on in that area. In addition, your stars all are coloured in a consistent manner and allow for objective comparison of their temperatures.
[rant]It's 2014 and people think it's still okay to stretch their colour information along with their luminance information. Just because you stretched your data in a certain way (or picked a particular exposure length) doesn't mean that things magically change colour out there in space just for you! Colour should be rendered as it truly is; a ratio of photon emissions as measured at particular wavelength intervals. This ratio is a constant - it does not vary depending on your exposure length and you certainly should not be altering that ratio arbitrarily by applying the non-linear stretching you perform on your luminance data to bring out detail. Nope, sorry, stars are not all mostly yellow (or some other random colour you picked), they are an even mix of all color temperatures combined across a large enough field. We can argue until the cows come home about which shade objects are exactly or how saturated something should look (this is subjective), but depicting colours differently depending on exposure length or depending on your luminance processing technique belongs firmly in the era of film photography (which is fine if you want to emulate that look, but it's not very scientific and you're doing the viewing public a disservice by distorting reality and making it hard to compare things in your image and between different images). I wish more people would render their DSOs like you have done here in this faithful M8, where information conveyed by colour has been maximised.
[/rant]