Over time I've come to prefer Vallejo Model Color for most everything. It has everything I want with none of what I don't and that's good enough for me.
The characteristics of that paint that I like are the dead flat matte finish, the consistency of the paint from color to color, the densely pigmented paint, the lack of any funky additives and the ability to cover well or layer with very thin coats depending on the need.
There is honestly nothing I don't like about that range. The only thing that used to bother me was the endless shaking and mixing, but I now use a shaker to take care of that, and mixing is just a part of life, doesn't bother me.
I own the range of Reaper MSP and VGC and I only use those for "special effects" and have been very tempted to just sell the paints outright lately as I rarely use them and I still need to round out my VMC collection.
Not here to bash the paints just to say they don't suit my preferences and techniques, so I will mention somethings I like and dislike about both ranges, of course, in my opinion.
Reaper MSPs, what I like about those are the ability to glaze with the "Clears". Very nice paints for glazing and I lean on those clears quite a bit. Let's see. The "Bone" colors are nice and I like the Rosy Skin triad, but only for highlighting. Most of the paints make a good shadow color if you use shading techniques, and mainly that's what I'll use these for when I reach for them since they take alot of water pretty well and can get some nice subtle shading effects. Layering with them is an exercise beyond my level of patience however and I count myself an extremely patient person. You can spend a small eternity layering between two tones and eventually get to a great level of smooth blending but you can achieve the same effect in a fraction of the time using a different brand of paint. They are just too much of a "soft touch" paints for my hand. They're good for washing and "staining" techniques though since they take alot of water pretty well, but the satin sheen just kind of kills that joy after awhile. Great color range though if you don't like mixing, but...painting with those colors is hard for me, I just never got the knack for those paints really.
The downsides to MSP (for my preferences) are the satin sheen, the weak coverage, the inconsistency between color ranges, the inability to come up with a uniform ratio for thinning as each paint color needs it's own amount of thinning to be able to control. The addition of flow aid, which is a real beast when you simply don't want any additives to your paint due to their unpredictable behaviour at times.
On to VGC. I've tried to get a handle on those paints for years and I've finally found their niche, which is strictly use for base coating or shooting through an airbrush on tabletop gaming pieces of my own. They have a unique "one coat" coverage (depending on the color) that can be useful if you're just painting minis to knock out for gaming, but I just don't have the ability to use them for much of anything else other than that and painting bases and such.
Upsides, they are useful like I said for one coat coverage. They don't even need to be thinned for that purpose if you're ok with a brushstroke here and there. They're durable.
Downsides. Can't do much of anything with them as far as layering techniques, mixing colors, incompatible with other ranges, satin sheen at times, high separation of binder to pigment causing unevenness, doesn't take to thinning well for advanced techniques, plasticy consistency.
Again, I'm sure masterpieces are painted with both ranges in entirety. But me, I've never been able to get the results I want from those paints and fight against them, whereas Vallejo Model Color goes with my preferences like a hand in glove. If something works for your style why go elsewhere right!
