Last long? I've had two bimetal hacksaw blades on my bench for years now, one in a saw frame, one free. Not that I do a great volume of prototypes here, but both still cut FR4 just fine! Noticeably dull in the high-use spots, but not too much is needed as the resin part is soft.
Fiberglass, it's a material that's rather soft in bulk, but highly abrasive when cut. So, steel tools for example can do fine, they do dull quickly, but they are useful to a duller condition than when cutting steel for example.
I have a couple other plain steel tools, that I use on FR4 from time to time, and resharpen regularly as such. One (a scraper made from the broken tang end of a dull file), every couple of boards say; another (craft blade), constantly because it's made of painfully soft (spring temper?) steel that can't even hold an edge cutting wood or paper...
Also have a couple carbide drills, because drilling is fairly nasty in comparison, drills are harder to sharpen free-hand, and you tend to be doing a lot of holes at a time. HSS or even carbon steel is fine for a few to maybe hundreds of holes, that's about it.
Tim