I disagree. Whenever possible, you should pull the plug and drain the oil that way. MB (and most vehicle manufacturers) put it there for a reason: Sludge collects on the very bottom of the pan, as does other various matter, such as metal shavings. While suctioning can get most of the stuff out, it leaves that very bottom layer of gunk on the pan, and does not clean off the "stuff" on the end of the drainplug (for those who do not know, most oil drain plugs are actually magnetized to attaract metal particles).

The trick when pulling the plug is when you reinstall it, do not torque it within an inch of its life, as many amatures do, as they are afraid it will fall out. If you properly torque it, it should last a long time, as will the seal on it (if so equiped).