I dump DE blades after two shaves, just because I have hundreds of them and after two DE shaves I need to go back to SE.
Injector blades vary. Personnas last 5 shaves for me, Chinese Schicks about 10 shaves, Schick NOS Twin blades 10-20 shaves, Personna 74s 15-25 shaves. So, value for money, the Personnas even though they last the least number of shaves are best. I still won't buy any more, because the Chinese Schicks are so much better and the plastic dispensers are crap. Personna 74s last the longest, but are not worth the £3/blade I paid. If you see any Schick NOS Twin blades on ebay, don't buy them. They're mine.
That leaves Japanese Twins (weird bunch, between 1 and 10 shaves, currently overpriced) and Proline blades. I haven't made up my mind about Prolines. The first shave is outstanding, then most, but not all, seem to decline quickly. I need more shaves with them.
My personal choice from current blades are Chinese Schick blades. They last, are sharp and smooth and reasonably priced.