I use Onyx Thrive. I find it's the best fit for most shops honestly. Caldera is the most popular but it is lowest on my suggestion list. Print Factory is the highest end of control, features, and power, but is overkill for the average shop. The only right answer for you is based on who's build style and features you can use most effectively. All rips have tons of automation features and workflows to really blast through production, but for people who will only go so far as to set up every single job manually ... feature and RIP differences really don't matter at that point.