It's all preference, bud. They really don't take long to complete, either. Hell I think I finish one a week. And that's maybe a total of 18-24 hours.
Pioneer gives you boosted experience gains per match. It's useful if you're in a hurry to get through the specializations.
Just know that if decide to work through them all; the last one you finish will be your permanent title (I didn't know this, it kinda sucks for me). --- The official Sheogorath of The Elder Scrolls V: Skyrim. The right and Righteous hand of Whatnos