I also have one of the electric unit that runs on the car battery, but the Sealey's tubes are far better at making their way down the dipstick pipes as they are semi rigid.
Oil extraction pumps work very well (and is the method used by the dealerships) but not on models with a saddle sump and two drain plugs as you'll leave a significant quantity of old oil behind
I've got a Pela pump which works well but it takes a good half hour or so to empty the engine so you've really got to get the engine hot before you start.