Softener purchase guidelines/recommendations

[Boileralum]

I am in the process of researching water softeners and haven't found much in the way of solid advice / opinion as to what brands are good, which ones to avoid, etc. I plan to install myself. Are separate components better than the single housing models or is it just a matter of aesthetics? Better to buy from national retailer or can I get the same or better value (price to performance) by purchasing online? Our water source is a water company and the hardness is around 24 gpg and usage is about 5000 gal/month.
I know that the forum doesn't allow specific brand endorsements or advertisements. Please post some general guidelines here and, if you are willing, e-mail me the specifics on brands. Thanks.

Gordon