When you're painting miniatures for a Warhammer 40k army (or any other table top wargame for that matter), the type you choose is insanely important. With the number of paints and types available on the market, it's easy to get a little overwhelmed with the choices. Acrylic or enamel, this brand or that, the only real way to know for sure is to try them and that can get pricey.
I've used Games Workshop, Testors, P3, and Reaper Pro Series, and I have things I like about each. Except Testors. No thank you to enamels. But that's just my personal preference :)
I'm not a big fan of Games Workshop paints, but their washes are phenomenal. The paints tend to get thick and chunky unless you water them down, and I really don't like to have to do that. I prefer to paint straight out of the pot. The recently released their washes, though, and I was hooked. The GW washes fill into detail cracks and crevices like you wouldn't believe, making them pop, before trying to a killer satin finish. It's great for everything from weathering to adding a sickly pallor to your Chaos Lord's armor. I went ahead and got the full set, but the ones I'd say are a must have for any paint collection are Badab Black, Devlan Mud, Gryphonne Sepia, and Ogryn Flesh. The Asurmen Blue and Baal Red colors are good too, though I use those less. I, personally, find the Leviathan Purple and Thraka Green too bright for what I use it for, though. But that's merely a matter of preference. I also keep a couple of their foundation paints around: Tallarn Flesh and Astronomican Grey. These tend to have a bit of texture to them, so I like using them for things like skin or stone.
Next up is Testors. They've been around forever and I think we've probably all used them to paint up our model airplanes at some point or another. They paint well, and they're typically easy to use. My main issue with them is that if you need to strip your model after painting it, it's difficult to do without using a solvent that may potentially damage the plastic bitz. That's a big downside to me. I do, however, like their black base spray, even though I usually do my black base coat by hand anymore.
Privateer Press (makers of Warmachine and Hordes) has released a line of paints that I was absolutely in love with for a long while: P3. Their paints flow smoothly and have a great selection of colors. I definitely still love these paints, even though they've been dethroned as my paints of choice. While you don't have to water them down to get a nice consistent flow, they suffer from the same chunk issue that GW paints do, except you've got a lot more time to work and a lot less chunk when it does. The other issue that I have is that their lighter colors (yellow, orange, etc) tend to paint on a little thin, requiring a couple of coats for adequate coverage. The one thing that still hasn't been replaced as my faves are their inks. Their inks are ridiculously vibrant in color and have a great stick to them. They're awesome for adding some cool highlights to metals, or giving gold or copper a verdigrised look.
Now... I saved the best for last: Reaper Master Series. I have never worked with a paint as smooth, with as good coverage, and as easy to work with as the Reaper Master Series paints. With over 200 colors to choose from (many grouped into handy Base-Shade-Highlight triads) you can come up with all sorts of different combinations for your army. The finish is extremely smooth straight out of the bottle, and you can use their additives (like Flow Improver or Drying Retarder) to change the way the paint flows to help with layering and shading and other techniques like that. As of yet, I haven't tried their washes or metallics, so I can't speak on their quality, but if its half as good as the paints themselves, they rock.
My paint setup is like this:
Paints: P3 and Reaper Master Series (slow phasing out the P3s for the Reaper stuff)
Washes: GW washes all the way. Absolutely awesome stuff.
Inks: P3. I haven't found nicer inks as far as hue and stick goes. love it.
As of right now, I'm using the Reaper brushes as well. They seem to be the best bang for your buck and they stand up better to use than the GW ones do. I haven't tried P3's brushes yet, but I'm in dire need of replacement, so guess which ones I'm gonna pick :D
Have you guys had different experiences with these paints? Let me know! I'd love to get some good ole discussion going here :D
Prosper, as Tau shall!