Is the 60T blade that came with my Dewalt DWS780 miter good for general purpose cutting?
A 60 tooth is a fine blade for semi-smooth finish cuts. Cuts on flooring are always at the wall ends, so even a 40 is good for that since the baseboard trim goes over the cut. You should be leaving a 1/4 inch expansion gap at he ends anyway, so they won't show. The DeWalt 12" blade is a good long lasting blade. It has good balance, heat dissipation and takes a beating.  I have several Dewalts and some other much more expensive blades for my 12' DeWalt double bevel chop saw. For most applications, the DeWalt is perfectly fine. If you start doing precision cuts in $6.00/foot hardwood cabinet crowns, then buy a $100 to $200 blade. Judging from your question, you are not to that level, so the DeWalt is a fine choice.