I also bought into the Ryobi One+ system of tools. The drill, small impact drill, circular saw and hedge trimmer are GREAT for the home user. Get the big batteries and they will keep up with all the big name brand models for contractor level work. That said, I bought/tested the 1/2" impact and returned it. It couldn't break loose lug nuts at 80 ft/lb on my BMW, so it is no good for heavy vehicle use.
You do have to keep NiCD batteries topped up (NiMH too), so you would have to think about how you will use the HF tool. I plan to buy a spare battery, look for some LiON replacement cells and rebuild the HF battery with the LiON cells. The one worry about LiON is draining them too low and burning out a cell, but they make versions with circuitry built into them that prevents draining them dry and there are even 3.6V (3100mAH) versions that might work. I will add to this thread when I figure out if we can safely upgrade the NiCD battery case to LiON cells.
As far as torque wrenches, the traditional straight beam torque wrenches are accurate and never go out of calibration, but our arms shake when we hold stuff so it will only be as accurate as your muscle twitch can do. The clicker types we all know can be off upwards of 10% in their readings, so a clicker is fine for most rough work but for engine or small machine assembly I highly recommend either a good digital or break-beam torque wrench.
I have the same experience as BurbMan. The HF Pittsburgh line of tools look/feel just as good as the Craftsman sold today. I have worked my HF wrenches HARD on my RV and they have been fantastic with no damage even to the finish. HF even honors a true lifetime, no hassle tool replacement on the pro-line of tools. Craftsman stopped honoring that policy years ago.
Jose