Filling wood voids in siding
I have used all three products. The bondo is the exact same thing as the Miniwax product, with the exception of the color. The cream hardener is the same the smell is the same, the handling properties is exactly the same. The painters in the high end company I used to work for used bondo in the appropriate places. As in not large areas, but for screw holes and perhaps a knot hole but no bigger.

The Dap product is good but you will waste a lot since it dries out incredibly fast. You MUST keep the top on at all times. Keep the lid between the fingers, hinge it back, take a dip of the filler, place it back, and hope you still use it before it dries. It will dry fast on the knife as well, so keep scraping it off as you go or your filling will take a lot of sanding. Personally, I prefer not to use it, although for small projects and availability I have used it recently. Neither the Dap, Miniwax or Bondo is easy to sand.

If all your repairs are small, the bondo will work very well for  you. If the repairs are large, say bigger than a quarter, the wood will move and crack around practically any repair you make. With any product you use. You may be able to go a little larger than that, but it depends on the siding and how the wood is cut, as in flat sawn, quarter sawn or rift sawn, but that is another lesson.

7/8/2016 Edit

The picture tells another story, it helped a ton. You do not need filler, except for the knot hole in the second picture. Either product will work there, otherwise the wood needs only to be properly prepped for painting. Resetting the nails that have popped out a bit and maybe filling those with with an exterior grade filler. If they were just set flush and painted over them has been the norm for ages.

The finish is cracked due to the expansion and contraction of the seasonal changes. That is the biggest problem. Getting the surface sound enough to take a latex primer that will give and take with the movement of the siding will be the first step then a latex paint for the finish coats as well. I used to use only oil based primers back in the day, but they are a brittle finish and will crack again just like the finish you have on the siding now. The thing is, no matter what you use, whether it be bondo, or the dap product,or even something as mundane as caulk in the knot hole. make sure the wood is sound and primed before you apply any caulk in any place. Bondo needs bare wood in my opinion to hold, as does the Dap product, If that is used, be sure to prime and paint ASAP.

In my opinion, I would prep the siding for paint, remove all old caulk, prime everything, fill the knot hole with caulk as well as all the joints to the brick, except for the joint at the bottom to the sill ( caulk holds in water as well as hold it out) DO NOT caulk the wood panels together since it looks like you have a board and batten siding detail, and finish paint. Wood needs to move, and it WILL move, caulk will try to hold it in place and cause cracks in the face.

The nails need more attention than I explained at first but it is a matter if the nails that are "proud" are actually holding anything. They either rise off the surface by everything shrinking away from the nail head or the nail point is not in anything substantial and therefore loose and not holding anything. Some of the nails in the siding are overkill, it only take 2 nails in any nailer in the wall to hold siding in place. The third one in the middle gives reason for the siding to split, you are lucky in this case.