Artist quality have higher pigment levels, better color options, less color change as it dries. Some can be expensive but you can start with artist grade and not the top of the line as there are levels in this grade as well.
Student grade usually need more for same coverage, bigger changes in color as it dries and even wet with less pigment concentration. Really not suitable unless you are a student and have to save money. Still, it caused me more problems-and the quality of the finished product with artist quality is worth the extra $.
This thread talks about different brands: What brand of oil paint do you use and why?