I've been using a Topsider for about a year now and although it works, it does have some quirks. The biggest problem I've had is the suction hose is too soft and collapses when you place the recommended amount of vacuum (pumps) on the system. It takes a few extra minutes to extract the oil because of this. Another problem is if the oil is too hot, it will melt the end of the plastic hose which could be very unhealthy for your engine if it broke off inside the dipstick tube. So let the oil cool for about 30 minutes after driving and it should work OK.
For purist, like Larry Bible, letting the oil sit for 30 minutes prior to draining would not be acceptable but I think the tradeoff is it makes oil changes so easy people are apt to do them more often and reap similar benefits in the long run. Lets face it, this level of attention only matters if you expect to keep the car for a very, very long time. To borrow a phrase fron Nike, "just to it" and often.
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