here's what consumer reports says:
November 2004
Freezing for the long haul
IT'S A WRAP The Food Saver Professional ll is very easy to use, but the plastic wrapping supplies you need to use with it are expensive. The device's most practical use is for long-term freezing of costly foods such as steak.
Vacuum sealers can prolong the life of many foods. But the price of the eight machines we tested ranges from $80 to $290 (not counting the refills of brand-specific plastic). That's a lot to spend on a pound of bologna or a package of saltines. The calculus changes, however, when the items you bought in bulk, and want to preserve for months, are expensive cuts of chicken, fish, or meat.
Convenience and cost. These don't go hand in hand. Both the $290 Food Saver Professional and the $85 Rival Seal a Meal are top-rated for convenience. They practically run themselves: Feed in the plastic; the sealer swaddles the food and sucks out the air. You slide a cutter across the sealed package. With the other machines, you have to use scissors to cut off the package.
Sounds good--until you figure the ongoing cost of storage materials: 45 to 74 cents each for plastic bags in gallon and quart sizes; 45 to 70 cents per square foot for rolls of plastic. That's 10 times the cost of regular, zippered freezer bags.
The freshness test. Vacuum sealing almost always worked well. Although beef and salmon steaks frozen in zipper bags and containers suffered from freezer burn, those that were vacuum sealed showed little or none. Sealed and refrigerated cream cheese stayed fresh for nearly a month, while cheese stored in other containers had mold. However, containers and zipper bags did better at keeping lettuce and celery crisp. And vacuum suction crushed bread and pound cake. Potato chips, cookies, and crackers picked up off-flavors from the Rival plastic.
The bottom line. If you regularly buy food in bulk, a vacuum sealer may be a good investment. The Food Saver V840 offers the best performance for the price.