SpaSearch.org, Pool & Spa Living, PoolAndSpa.com and HotTubSpaRatings.com all provide useful (if somewhat general) information about above-ground acrylic hot tubs, including buyer's guides, photo galleries and comments from owners.
Acrylic or OAS (olefin acrylonitrile-styrene) hot tubs with a fiberglass or foam understructure and a wood or synthetic cabinet are the most popular type sold in the U.S. Although these hot tubs are considered portable, they are fairly difficult to move and require a firm surface, such as a concrete pad, for proper installation; some models also need a special electrical outlet. The main drawbacks of acrylic hot tubs are a tendency for their surfaces to bubble or crack over time after prolonged exposure to sunlight, their high electricity costs (up to $50 per month) and their high price overall. Still, with over 100 manufacturers and countless options and add-ons, acrylic spas remain the best all-around choice for most families. If you're willing to make the investment, you may also want to consider an in-ground spa (*est. $5,000 and up), which has the added advantage of raising your home value.
This website includes dozens of articles related to hot-tub buying decisions, including sections on construction, features, maintenance, safety and installation, and a photo gallery to give you an idea of the various types of hot tubs available. Most major brands are included in a customer survey posted here.
Review: Buying a Hot Tub, Editors of SpaSearch.org
2. Pool & Spa Living magazine
There are no reviews here, but you will find some good articles on choosing a spa, as well as on installation and maintenance issues. This site also runs lots of photographs of fancy and not-so-fancy spas, so you can get a good idea of what's out there.
Review: Hot Tubs and Spas Articles Archive, Contributing editors to Pool & Spa Living
This retailer sells parts, chemicals and accessories for hot tubs, but not the tubs themselves. Most of the site is very commercial, but the article on buying considerations is helpful. The short guide covers material types, installation considerations and a shopping checklist.
Review: Planning to Buy a Hot Tub Spa?, Editors of PoolAndSpa.com
4. HotTub SpaRatings.com
An extension of Robert's Hot Tubs, a California-based manufacturer of wooden hot tubs, this site has user reviews at a huge number of spas. Very few owners post comments for the same spa, but there's a large enough number of comments here that you're more likely to find something on the spa you're considering.
Review: Hot Tub and Spa Reviews, Contributors to HotTubSpaRatings.com