If the B&D blade is tungsten tipped and in reasonable condition, it should be ok. You pay more for ease of use and accuracy of adjustment, but hardly important in this case. Sorry, you can't buy a new one :-)
Probably the biggest difference between cheap and nice circulars is the quality of cut. I've got one that produces a perfect edge with no packing, and another that does its best to make a mess. Putting hardboard, or any other scrap, on top of the piece being cut makes a big difference, it stops the blade tearing lumps off the laminated surface.
Can you get a nice new one? If you want. You'd get a nicer result relatively easily.
TCT blades last a very long time, but if your prospective machine has replacement blades at screwfix.com and toolstation.com then you're on pretty safe ground.
If the B&D is old enough to have untipped steel teeth, ugh, go and get a rexon/makita/etc, you'll be delighted.
NT
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