I'm on a well also. I have a Kent Maxxima unit in which I replaced the filters. I currently run a 5 micron prefilter, 1 micron prefilter, Dow Filmtec 75gpd membrane, and 2 DI resin post filters.
I run the micron filters to protect the membrane from the iron particulates in my water, which has seemed to work well, the membrane is 3 years old and still achieves 98+ % rejection. I also feed the unit with softened water, that probably helps as well.
I use a booster pump to deal with the cold water input, I'm not exactly sure what my production is but I think it's pretty close to the rated 75gpd, even with the cold feed water.