Me personally I love both, to me the tenderloin is a better cut but they can be pricey. Most of the time I will grill the tenderloins and smoke the loins, so it becomes a question of how much time do I have.
This is a recipe I found here awhile back for Tenderloins, I wish I could remember where I got it so I could give the proper credit, but anyway it is awesome and the family loves it
Awesome Pork Tenderloin
1 1/2 lbs. lean pork tenderloin
1/4 cup soy sauce
1/4 cup brown sugar
1/4 cup cherry cola
3 tbsp. olive oil
1 tsp. minced onion
1 tsp. black pepper
1/2 tsp. salt
1/2 tsp. minced garlic
6 oz. cherry preserves
1 tbsp. pure maple syrup
1/2 tbsp. vinegar
1/2 tbsp. water
1/2 tsp. Worcestershire sauce
The night before (or several hours before) , combine marinade ingredients and mix well. Place pork tenderloin in marinade, and refrigerate for 4 - 12 hours.
In a small bowl, combine glaze ingredients and blend well.
Build a charcoal fire on one side of the grill, such that the coals are situated on only one side of the grill, leaving the other side void. This will create an area for lower temperature indirect cooking away from the coals. Preheat charcoal cooker to 250 degrees F. Place tenderloin in cooker and cook with indirect heat for 1 hour and 15 minutes.
Brush glaze onto pork while still on the cooker. Cook for an additional 10 - 15 minutes. The internal temperature of tenderloin should be 160 degrees F when removed from the cooker. Heat any remaining sauce and serve on the side.