You know what, crossing is not hard whatsoever; personally I find it "harder" to clone than I find it to pollinate and create my own genetics, besides, it's hella lot funner, so damn interesting, and you get to create and pick your own variations depending on what you cross. If you want to maintain one particular strain because you like it, you simply in-breed it, so wait for a male to pop up put it in a different room all-together from your flowering room, and when you see a big mama that you are really interested in, or that you believe will bud with the most of your desired traits, then pull that mother and you can pollinate it with your male. There is much more advanced methods that one can use, but it's very risky. For example, I taught my friend a trick and I have been working on creating custom genetics/strains for him on his plants. I am not gonna give away the entire secret to the trade, but I will say this: it is possible to use the pollen from any variety of males you would like (20-100,000 different strains of male), with any number of variety of plants you have entering flowering (So let's say you have 20,000 plants in flower, and of those 20,000 there are 5,000 different strains or variations of strains. Well, essentially I can guarantee you that it is possible to cross-pollinate any number of females in the exact same room and not have contamination in regards to cross-pollination of an undesired strain or in regards to causing seeds to grow on buds you wish to have no seeds whatsoever.
Some people find cloning easier. . . If I were doing my own grow, I would certainly prefer making my own seeds.