I use a chip brush when I want to apply more pressure than a foam brush can take. Home Depot brushes are good enough for me, though I do check for shedding after each use 

Laszlo

   Same comment as Laszlo about the pressure. I predominantly use a chip brush (or plastic scraper, spatula, or popsicle stick-type filet tool) when "applying material" and a foam brush (or roller) when "applying a finish."  So, I use a chip brush to glop-in a corner filet or to wet out areas of fiberglass cloth in corners, etc. where a plastic scraper/spatula isn't the best. Stipling the bristles of a chip brush down into fiberglass can help with wetting out. I use a foam brush (or roller) for applying epoxy on surfaces that need to look nice, or when applying paint or varnish. Basically, use whatever works best.

  I'm not sure any brand is better than another. I'm not even aware the things are actuallly "branded," or even that the retailers of the brushes use anything other than the (Chinese?) supplier that offers the cheapest wholesale contract that month (or whatever).  So if you think Home Depot has better brushes than Ace, I'm guessing the opposite might be true at some point in the future. 

The real question is how to make any cheap, disposable chip brush work better: First, brush the fresh, dry brush firmly against your pant leg or a rag or something, then gently pull/tug out any loose bristles with your fingers, then run a bead of superglue completely around the circumfrence where the bristles meet the metal band, then trim the ends of the bristles just a bit with sharp scissors to get a more uniform/flat tip to the brush, then again brush the dry brush on some cloth to try to remove any loose bristles, cut-off remnants or dust remaining in the brush.  I do this even if only using the brush to do rough work.  Even so, after this treatment (it only takes a minute of two and 10 cents worth of super glue) the chip brush will rarely leave bristles in your work, and will actually "paint" a pretty good finished surface - though (again) I don't use the fixed-up chip brushes for finish work. 

I get my chip brushes at Harbor Freight at about $0.60 each, and they work just fine. They're almost $2 at Home Depot.  Same for acid brushes, which are $0.09 each at Harbor Freight and $0.30 each at Home Depot. (Coincidentally, both of those are right at 3 1/3 times the price at HD)

https://www.harborfreight.com/3-in-chip-brushes-12-pack-58086.html

https://www.harborfreight.com/12-in-horsehair-bristle-acid-shop-brushes-36-piece-61880.html

I wrap a a piece of packing tape around my hand with the sticky side out, and then scrub the bristles against it to get out any loose ones.  It doesn't get them all, but it gets most of them.

Thank you to the three of you for your insight and experience!

Mike