We bought a K-Tec so long ago no longer remember when we bought it. Then, they had only the FourSide jar, the seal went out right at seven years, they replaced it under warranty. We bought a second FourSide jar, had it shipped with the warranty replacement. K-Tec still works but getting "loud", one jar seal now leaking. Bought the new Blendtec Designer 600 (a Costco special set) a couple months ago that included the WildSide jar and the Twister jar along with all the recipes, etc. Now ordering another WildSide jar as we often need two for food prep. We are sending the K-Tec with FourSide jars to our sister-in-law who does catering in SoCal. Even at well over ten years old, it still works better than the much newer "best there is" (name brand omitted) she uses.