The webers are difficult (compared to a good smoker) to control, tend to run "hot", require a water pan as a heat deflector, and for longer smokes require you to add charcoal and water. There are many people that use them, they're cheap, but IMHO you will be more frustrated trying to get a recipe to come out good than its worth. Most neighbors who have bought one, either sold it, or only used it a couple times.
There are many smokers available (offset, reverse draft, etc) and if you plan on cooking large amounts at a time (4 pork shoulders or 3 briskets) I'd recommend an offset smoker. They have the fire box on the side, and a large barrel type cooking area.
For smaller cooks, 1-2 briskets or 3-4 racks of ribs, I don't think you can beat a ceramic type cooker such as the Green egg. I've got the large egg and it holds temp very well, can cook 24+ hours on a single load of charcoal, meat stays moist, and it uses a ceramic heat diverter (no water needed). I've added a BBQ Stoker fan control to mine for the long cooks and remote meat temp monitoring. That's a tool I'd recommend for any smoker. Great piece of mind.
The Eggs are expensive, but their flexibility helps offset the cost. You can cold smoke cheese, sear a steak, or do a turkey (my turkeys have always sucked). The insulation again is a huge advantage over a standard grill or smoker. I'd recommend you buy the largest egg (or smoker) you can afford. I'm almost debating getting another large egg for the few times a year where I do larger cooks...... I tend to run out of space.
A couple other notes. Smoking and temperature control is all about air control. Any smoker you buy should have seals on the lid or door and dampers that have a good close fit (especially the inlet damper).