Meg's APC plus is a pretty good all around product. If you find yourself standing in front of a very dirty engine, APC+ will do the job but I generally find that Meg's SuperDegreaser will make the work easier. Others may find APC+ does just as good of a job but my experience is that SuperDegreaser is stronger.
In the past I noticed water beading on my microfiber towels when I only used detergent. I assume that is wax/sealant or oils from the glaze/polish/AIO/paint cleaners causing this. To get that stuff out, I also used to pour a cup or two of Meg's APC or APC+ in a load of laundry along with an ounce of Dawn then afterwards clean them as usual with detergent. This did a pretty good job of cleaning the towels enough that beading no longer occurred and their absorbancy increased back to when they were new. I now substitute SuperDegreaser instead of APC or APC+ and I think it does an even better job.
Lastly, if you see something on your paint and APC+ is even having trouble removing it, a solvent may work better. If you like the Meg's line their Detailers Line Body Solvent should work fine.