There is no "best place" there is your personal favorite place. Some have a favorite style of play, a favorite field owner/ref staff, a favorite actual field to play on, or a favorite group of regulars that show up.
North of Detroit (but still on the east side) there are:
- CRU Paintball in Flint (indoor, outdoor, speedball, woodsball)
- TCP Lansing in well... close to Lansing (outdoor, speedball, woodsball)
- Bandit Paintball in Saginaw (indoor, outdoor, speedball, woodsball)
West Side hides a few more fields and I may be forgetting one. I just included the ones that I'm fairly certain you will be happy with. Best answer is to try as many as you're willing to drive to and see which one you have the best time at.