Update: I ended up buying both a picnic and boston butt. Smoked them both side by side for almost 15 hours until internal temps reached 195.
Id say that picnic had a slightly better taste, as in solely the meat. I tasted from a part of the cut deep inside near the bone and as far away from the rub applied to the outside and also far away from the smoke. Picnic had a slightly better meat/pork taste.
However, Boston butt was MUCH more moist and juicy. I found boston butt had more intramuscular fat (big pockets of it) and as I was shredding it, the meat was dripping and glistening with pork juices.
I'm not saying the picnic wasn't juicy and the boston butt wasn't tasty. Both cuts were outstanding. I'd have to give a slight edge to butt for the juicyness.
I'd also like to share an error in my planning here. I started the shoulders on the smoker way too late in the day. I put them on around noon. I initially had wanted to start at around 8-9 AM but was delayed and started hours later. This was my mistake.
Pork shoulder need to reach an internal temp of 190-195. The test is to try to wiggle the bone. If it rotates and wants to pull out of the meat, it is done. If not, it needs more time. These shoulders were on the smoker for almost 15 hours. Therefore, I didn;t pull them off the smoker until almost 3 AM! Then they had to rest for almost an hour in a hot oven. Then I had to pick each shoulder clean and pull all of that pork. End result is that I did not get to bed until almost 5 AM. But I did have a good pulled pork breakfast before I went to sleep.
Next time I do this, I need to start early in the AM or start the smoking late around maybe 10 PM and let it go overnight. When when I wake up in the morning, the shoulder gets flipped and should be ready in time for lunch.