I have the same inflator, and it's worked well. I don't buy the expensive brand name cartridges, though. The unbranded 16g ones from eBay are about $1 apiece and are identical to the brand name equivalents.

As above; I just purchased an inflator that should be good for four tires (but not tested yet). A couple of times I've either been on pretty long rides (40 miles off road with 8,000' of climbing) or it was blazing hot with mosquitoes swarming and an inflator would trump a mini pump (which will be the back up). As far as forgetting to charge the battery, if I worried about that I might worry about forgetting to wear pants.