I use Bainbridge five space pliers. Mainly because I got them second-hand but brand new and unused for fifty bucks. They are the most expensive (here anyway) for the pliers themselves and the digits. I got a second set also cheap and only lightly used, so now I leave my breeder's prefix in one set of pliers, and change the other to give the individual id. Similar to what dun mentioned.
I like the simple, robust design of the bainbridge, however the main drawback I have found is that they are very heavy, I find it difficult when doing a whole day of tattooing (I am rather small and not that strong).
We use the Stone brand at work, they are the cheapest here. The model we use has the swivel head so one side gets individual id and the other gets stud prefix. They are lighter and smaller, so they fit in my hand better and they are not as tiring. They have held up just as well as my bainbridge ones, even though they are cheaper, and in fact they get more use than mine.
I havent used the ketchum ones.
If I was going to buy a brand new set I would go for the stone pliers. Cheap but no problems with them.
As far as ink goes, the green ketchum paste is best for all livestock. It shows up well in all ears, including black ears. Most tattoo outfits come with a jar of black ink. Most breeders chuck it out. Since I have angoras (white skin in ears) I get these jars of black ink free from producers in our area, its a cheap way of getting the ink!