From the original post, looking at the Cons:

Price isn’t an issue when you consider a standard pot is ~£3 but you generally need 3 or 4 of them (Base, Wash and either drybrush or two layers) – so around £9-£12 per “colour”. £5 per pot for something needing only a single coat is probably a net saving.

I don’t see how it behaving like airbrush paint mixed with flow aid is a “con”. It’s possible to mix your own washes and glazes but buying pre-mixed is both convenient and, for most people, more reliable.

Some shades work better than others in nearly every single paint range out there, including citadel’s regular layer paints

When I use colour primers I never paint areas of different colours over the top of the colour primer. I always re-undercoat the area.

Pots aren’t necessarily a bad thing, just GW’s pots. For everything except washes, glazes and airbrush I would rather have a pot, I would also rather have a better designed pot than GW’s current offering.

Looking at the Gotcha’s, GW’s main spray varnish has been satin for many years so this isn’t necessarily a surprise. However you should always varnish gaming pieces and so the finish you ultimately end up with will be dictated by your choice of varnish irrespective of the finish of the actual paint.

Big Brushes are hardly a gotcha. You choose the brush size appropriate to the task. This is true for all paint.

All paint has a primer Colour over which it works best. This is just another piece of knowledge painters need to learn.

Are they doing metallics? I didn’t think they were.