I use a much bigger Mityvac extractor, but it's the same idea. I love it.
My car was designed to have the oil drained with the car sitting level, as I think most cars are. If I wanted to drain the oil from the bottom, I'd have to lift all four corners to the same height, or else I wouldn't get as much oil out. But with the extractor, I can pull the oil out with the car on the ground, and then lift only the front end to change the oil filter. So, I get about as much oil out as I could by draining it from the bottom, with less work and much less spill risk.
For a car with a top-mounted oil filter, an extractor allows the entire oil and filter service to be done with the car on the ground.
You'll still probably want to drain the oil from the bottom every so often. But every so often is much easier than every dang time.
Couple of things unique to my application that are easier with an extractor. First, I change the oil more frequently than the filter, which is obviously much easier with an extractor. Second, I have oil coolers that hold a fair bit of oil; I can get some of that out by first pumping out as much as possible with the car level, and then jacking up one corner of the car and pumping some more.
Caveats: Pumping can take more time than draining, and at least the Mityvac doesn't like to sit with oil in it (it'll be fine until you go to use it again... ask me how I know). But that's all hardly worth mentioning next to the benefits.
So yeah, two thumbs up.
