I got mine from the home depot for $440 (w/ tax)
The impact feature is just so awesome. It can drive a 3-1/2" screw into a stud half way, stop, drive it 3" deep, stop, then drive it in the rest of the way, and then smash it half way through a 2x4 head and all, this baby has torque to spare. The impacting power makes it better than a 6amp coorded drill, and it's light weight and cord free. It's powerful enough to use spade drill bits to power through 2x4's. The impacting transfers the torque from the drill head to the screw, without torquing your hand.
I was trying to use masonry glue coated screws in wood, and once the masonry glue melted and froze the glue, this driver just impacted the head of the screw right off.
It's very small, about half the width of a normal drill. Most of the weight is in the battery. The batteries have great life, I can go half a day on a charge, and one of my spare batteries has held its charge for a year so far and only lost 1 bar of power(without charging it). A lithium battery runs a tool at full power then dies the second it runs out of juice. So you can go full speed right until the end of battery life. You can click the battery to get a color indicator of life remaining, a series of bars, like your cel phone battery shows. That can be a good thing to check before you go upstairs or up a ladder so your battery doesn't die when you're on a roof.
Changing bits is a breeze, you just pull the chuck collar out.
You can't use normal spiral drills with the chuck, but you can use hex shank drill bits. And if you want to do anything beyond light duty, stick with the M18 model over the M12's, the M18's are plenty light.
This is great for driving screws into drywall. Not as fast as a coorded VSR screwgun with a pressure engaging chuck, but as far as coordless tools go it's the best there is for driving screws.
The rafter hook I haven't needed, but I hang it from my belt once in awhile when I'm dual wielding drills.
The hammer and anvil mechanism is on the front of the tool and is steel. It looks like it will outlast the rest of the tool. I have seen a repair kit on ebay for $20, and it looks easy to service. The brushes on the other hand are imbedded in the back of the tool, and there are 4 of them since it is a 4 pole motor. Milwaukee 22-22-1630 Carbon Brush Card for Impact Driver for 2650-20 You can get a kit to replace the brushes for $10, which is a bit high but they look like good long brushes that shouldn't need much servicing.
I chose milwaukee over dewalt because milwaukee's clutch breaks in their coordless tools are metal. The clutch break is what stops the chuck from spinning when you take your finger off the trigger. No coorded drill I have ever used has had one, except Hitachi D13VF 9 Amp 1/2-Inch Drill and that's an electric brake, but it is standard on coordless drills, probably because they have less rotational force so are easier to make a break for. The break is great because you can take pressure off the drill the second you take your finger off the trigger without your bit jittering inside the screwhead like a coorded drill would do.
This is best for drilling holes in wood or concrete but you can also fasten with it. You can torque it up or down if you are drilling into pressure-sensitive material. It also has speed settings so you can drill or fasten slow-fast. And the trigger itself is variable speed so you can use a feather touch. In the hammer drill setting, small holes in concrete are a breeze. 1/2" holes in concrete are pushing the limits of the drill. It has no trouble with 1/2" holes through metal.
All metal guts. Metal head. Plastic bit sleeve (rotates to release saw blade). This has great power and cuts through 2x4's easily. It can also cut through thin metals easily. I tried cast iron pipe and that chews up batteries too quick for my liking.. unless you only have a couple small pipes to go through. Sometimes I'll use it to prune small branches in the yard. Typically I use it to cut recycled 2x4s or 1x3s that have lots of nails in them. If I hit a nail with a reciprocating blade it's not a big deal.. most of them are designed with that in mind. It's also great for plumbing, cutting large pvc pipes for grey water and black water. They make an 18v one hand sawzall that I have that is pretty good too. Better for plastic plumbing pipes. It's safer to use around water than a coorded sawzall.
Projects about 50 feet and has good battery life. You can buy an LED conversion piece for $25. It's basically a freebie. No one buys these kits for the lights.
I find myself wanting the M18 circular saw, jigsaw, and angle grinder often, but they are about $30 more expensive than other brands, usually over $100 when I see them on amazon, even used. Probably since they are so well made they don't really break or get refurbished, you're stuck buying them new. I guess that's a good thing if you buy into this battery set.
The M18 set also has a couple sizes of impact wrenches, electric caulk gun, a hand held bandsaw, jobsite radio, and some other less traditional battery tools. Their M12 line has the trade specific tools like voltage meters, rotary tool, oscillating multi-tool, and pvc clippers.
Hope this review helps!