Back to the topic at hand. Now living in Texas, probably the Meat Smoking Capital of the Country, dare I say the world and having a previously acquired hunger the for smoky deliciousness of low and slow cooked proteins, let me see if I can unwind this question.
My Dad, recognizing my natural culinary talents having put delicious food in his belly for years, bought me a barrel style offset smoker for Christmas one year.
It was low end, leaked smoke all over and thin gauge metal made it difficult to hold heat. I hit the old interwebs and began my research on some of the characteristics of a good smoker. To break it down, there are a few things to consider when looking at any smoker:
1, Build Quality. Thin gauge metal does not retain heat well and will require more fuel and tending to keep your meat at the right temp for any extended period of time. Also don’t want anything that has cheap Tack-Welded hinges as it will likely fall apart after a season of use. Thick Ceramic coatings on the exterior surfaces will improve heat retention and stable cooking temps. Some feature a ceramic liner, lie at The Big Green Egg.
2, What style smoker you want can determine the results of your cooks. There are several types of smokers. The earliest type were vertical drums (think 55 gallon oil barrel) that had a fire near the bottom and meat on a grill at the top. They work fine, but for the effort it took to keep running at the right temp on long cooks, there wasn’t much cooking space. Then they figured why not turn the barrel on its side and cut a door out. You could quadruple your cooking space, but now the meat was right over the coals. Not so good for low and slow. Then came the offset smoker where they attached a separate fire box to one side and use exhaust gases from the fire to heat the barrel as it passed through (pictured above). This is now the most traditional method of smoking meat. Many iterations have come and gone, but probably the best improvement was the Reverse Flow setup that provided a more uniform temp across the entire grill grate compared to the previous design where smoke enter one side and exited the other.
Now in the age of Modern Technology, you have lots of options available to you. The Pellet Grill removes the need for tending the Smoking Source and are available in Gas or Electric heating sources with Electric being the least fidgety with their digital control boxes that maintain cooking temperature and steadily feed the smoking fuel (pellets). They even come with built in meat temp probes to monitor your cook from a smart phone or computer via Bluetooth or WiFi. The question here becomes how much involvement do you want with cooking your meat? Is it sort of Set It and Forget It?
3, How much do you plan to smoke at one time? Pellet Smokers come in the tradition offset style as well as Cabinet.
With a Cabinet, you can smoke a large amount of meat simultaneously as it is sits on multi-level shelves. Are you cooking for a small family or it this a commercial venture? My old neighbor back in Atlanta, GA was a professional chef and the one that got me started on smoking. He had a Cabinet that he would break out when he threw larger parties. Nobody declined his invitations! Best choice is to decide what and how much you plan to smoke on average per cook, then pick a size that will fulfill those needs near the top end, but not burning extra fuel at the lower end. For example, I have a 864 cubic inch grill surface and can cook 2 18 Lbs Briskets, 2 full Racks of Pork Ribs and a Dozen Sausage links at the same time (for different lengths of time). We are a family of 3 to 5 (Immediate or extended), depending on who is coming over, so yes, I enjoy leftovers. 
For me to break out the Big Boy, I would go All Out and put as much on as I can and reheat the rest for another day.
The root of the question is how much meat are you planning on smoking at one time? How little tending do you want to do during the smoke? Don’t get me started on the Rub!