I've been making regular seeds for almost 20 years now and only started using fem seeds twice. Now it's time to start making my own fem seeds then when I share to people that just want to grow some bud and don't get into breeding they get a girl from every seed.
Most of the plants I have going now are from fem seed or were gifted cuttings that I grew out and I don't have a male to get pollen from so it's resex some plants to get pollen or keep mother plants for cuttings and I already have 6 strains going with plants for another dozen in the next 6 months. The four plant I have going from regular seeds all have recently shown sex and they are all girls too!
When you cross two strains grown from regular seeds the plants grown from those seeds, (F1), exhibit what is called 'Hybrid vigor' and they do grow faster and yield better than their clones will. F1 seeds also vary a lot as some will be more like the mom and some more like the dad with about half a mix of both. This is where selecting for the traits you want really begins to make F2 seeds. While vegging rub the stem between your clean thumb and finger them smell them. You'll get different odors from different strains and even different plants from the same strain will vary in smell. Then you look at how the plant grows. Big and bushy is not always the best. If selected for size and yield alone you will actually end up degrading the plant's good qualities. Sometimes that iffy plant has characteristics like a killer buzz but lower yields so if crossed properly can transfer those qualities to a plant that has great yields and a stank you love but the buzz ain't so great. Talented breeders grow 100s or even 1000s of plants to select the few that will get them the ideal strain they are looking for.
I'm no pro but getting into the finer aspects of breeding and in a few years may have some nice stable strains I can be proud of.