First thing to do is buy a kit to test for the hardness level yourself, so you will know if the guy trying to sell you his softner is blowing smoke up your .... Most companies will send someone out to test your water, to determine what model you need. He/She will pour a glass from your faucet, and drop tablets in, counting them until the water turns color. The more tablets it takes, the harder the water, which means a bigger softner or more cash.
We bought ours about eight years ago, and did alot of research at the time. they're are or were only two type, electric and those that run off water pressure. With some you can't run the dishwasher and the clothes washer, or take a shower at the same time, because you will run out of soft water. You have to wait x amount of time for more to be softened. So make sure you buy one with adequate size brine tanks for reserve.
I settled on a Kinetico softner, that works off water pressure. We sometimes have unexplained power outages in our area, electric coop, for a few seconds or minutes, so I didn't want to hassle with resetting an electric one. This bad boy has two large brine tanks, and let me tell you, with my five, five children and me showering in the moring, we have put this thing to the test. My wife is constantly running the dishwasher and washing mashine. the softner hasn't failed us yet. It's kind of pricey though, installed with a full load of salt was just under 2k. Oh yeah, we use about 3 40lb bags, Iv'e found "Morton" brand to be the cleanest, each month. You will probably use 1.
We only has one house sediment filter, which does a great job. I use the filters that look like a ball of yarn. If you have other elements that make your water taste bad, a dual filter may help.
Anyway, I don't know if this helps, but there's my .02
the Kinetico site has some good info on hard water
Good Luck Bruce~