Personally at Aberration Pro Custom Tattoo we have a few artist and with that comes different tastes in tattoo ink. I've worked with many inks over my 15 year career. I started out using Mom's back in the day when it really wasn't anything to talk about let me tell you. Today when of our best color artist use only Mom Tattoo Ink and his color blends are just out of this world. The ink goes in smooth and easy without mixing it with witch'es hazel or water. The ink settles great and stands the test of time.
As for what I use I'm sold on Starbrite and Intense. I really only like using the primaries because from that palette of ink I can pretty much mix any color I want. Over the years in my career I've used the clean and dip method but as time went on and different types of techniques came about I rarely use nothing but the mud and dip technique. I don't like throwing just straight black anymore without mixing it with one of the primaries. The only time I go straight black is when doing a Black and Gray piece but at the same time I stay away from the mixes or dipping method and use the needle to give me my different shades of black.
Outlining ink has been a tough change for me. I use to use Kumo Sumi but now I've decided to go with Dynamic Black ink from Kingpin Tattoo Supply. The black ink goes in just awesome and has a great tone to it. Kumo Sumi I've found has that problem of just lightning up way too much and lately isn't hitting the skin good. Kingpin Tattoo Supply sells the Dynamic Black in 8oz bottles so it's going to last you awhile. I use it for lining as well as shading.
Tattoo Ink is really just a preference of the artist. Some will do better then others. I never recommend going to off brands or tattoo ink made out of the country. The quality is very poor and it could be dangerous because it can contain toxins that the FDA does not allow. Before any artist settles on one brand of ink over the other I suggest trying them all out at least once. Always buy from a Tattoo Supply store that is reputable and sells to professional artist. There is Kingpin, Unimax, and a whole lot more. I would recommend staying away from Superior Tattoo Supply because they are way overpriced and cater mostly to non professionals. Places like Unimax, Cam, and Kingpin actually check out if your a legit pro or apprenticing with a shop.