Impossible to answer your question with no other information. "Softening" and "purification" are two very different topics. Every consideration for either/both must begin with an analysis of your water. Find out what you've got, then consider what may be required to change it.

Ok, water softener 101 ...

Get a water test from an independent lab. An independent lab has no agenda and won't be trying to sell you water treatment equipment. Go to http://www.epa.gov/safewater/labs/index.html to locate a certified lab near you. This is a MUST DO because without it everything is a guess. A quickie water test from Sears or a water softener company won't be as accurate (and possibly not as competent) as from a certified independent lab.

When you are on a well you have the responsibility of making the water safe and of acceptable quality. Acceptable quality is subjective but safe is not. Make sure the lab tests for potability... nitrates, bacteria, and such. Potability tests should be done at least once a year.

Living on a well is more work than living on a water system. There will/may be maintenance required based on water conditions and equipment required and well water conditions can change. Your well may have different water conditions from that of your neighbor's well across the road or right next door.

Hit the Yellow Pages and call at least three local water treatment pros. Make sure you call at least one of the big dogs like Kinetico or Culligan for comparison and at least a couple independent water treatment pros. DON'T TELL THEM YOU HAD YOUR WATER TESTED.

Give each an opportunity to offer suggestions and provide you with a quote to meet your water treatment needs. IGNORE ANY THAT DON'T TEST YOUR WATER THEMSELVES as they can't speak intelligently to water treatment without knowing what needs to be treated.

Ask lots of questions. Softening the entire house or just the water heater (bad idea)? Warranty, parts & labor or just parts, how long and on exactly what? Install, permits required, licensed plumber? Routine maintenance and costs? Do they stock parts? Response time for emergency (water leak) calls? If they don't explain things to your satisfaction that is a good indicator of how you'll be treated after the sale.

After they've gone use your water test to compare with theirs. Are all your treatment needs being addressed?

Ask your neighbors if they have any water treatment experience. They might tell you who's good or who to avoid.

Come back here and post the specific recommendations and hardware components with the costs and we'll give you our opinions.