Fresh! I'm a sucker for a well-planted tank. Plus SW is so overrated. There is one 3 foot grouper at work that I love though; he likes to splash students as they walk by...and he can move a lot of water.
i think a big part of freshwater hobbist enjoy breeding. there are only a few saltwater fish that will breed in home aquaria. probably more now, but still not as many as fresh, not even close. hybridizing, brings in a whole new part of fishkeeping that you cant get in sw yet.
a really nice planted tank is just as impressive as a reef tank. search takashi amano before you argue this please. and a nice african tank looks nothing like a amazon biotope if setup right, where most reefs look similar.
you can stock more in a freshwater tank with bigger more forgiving fish.
fw is alot less expensive. expecially for the AVERAGE hobbist.
sw does have 1 up on fw with the colors, but there are a few freshwater fish that come very close. dont think so? search for Aquamojo.
personality. dominated by the fw cichlid family. a few sw come close, puffers and moreys imo, but even a simple oscar is more fun to interact with.
Only problem being the start up costs can be astronomical if your not a diy'er. Also it only makes sense to keep a nano tank or a eight foot tank. Anything in between are useless.
I started with salt, but still love the simplicity of fresh. You can walk into your lfs and pick any fish you want short of a pima. Buy a large tank, a heater, a fx5, cycle a few weeks and your good to go. Doing the same with salt is impossible, ie liverock, skimmers, plumbing a wet dry, powerheads, maturing the tank for months, specialized diets.