Whole butterflied chicken is one of my favorites on the smoker - makes for a great lunch throughout the work week (just smoked a couple chickens last night).
The only food I haven't been tremendously successful with is brisket. Always comes out tasty but never as fall apart tender as I want. It's always somewhat dry.
There's a million ways to do a brisket - it's all about finding what works for you, not necessarily what recipe X says. Things I've found that are key with brisket:
- Digital temp probe - stick it in, be done with it. I'd probably advise retaking the temp (moving the probe) around the time you crutch the meat, just to make sure you find the coldest spot. IE, that 160 could be 145 if you move it over an inch. Crutched meat that I've done has always been a bit more juicy than non-crutched, although the purists will argue you don't need one if it's low and slow
- Moisture - pan of water providing moisture is pretty critical IMO
- Finishing temp - taking it out around 200-203. Recipes vary between 190-203, but 203 tends to be fantastic IMO
- Marinade/basting - not necessary IMO. I'd rather keep a consistent heat than screw up the temp every 30 minutes basting it with "flavor". Also do straight salt/pepper on the outside for the rub vs the 20 ingredient bucket list some call for. Also lets the meat shine through
- Wet aging - aging it in the cryovac for 30-45 days from pack date. Not sell by, but pack date. The last two I've aged for about 2-3 weeks each (2 for the first, 3 for the second) and it made a difference
- Smoker Temp - this one people will disagree about, but you're seeing competition folks abandoning low and slow for 5 hour briskets. To each their own - the last two I've done have been 5 hour briskets, and have turned out great for poker/dinner nights
Regardless, record what you do each time, and make adjustments off each one without changing the entire recipe/method of cooking.