Getting drum samples out of your head and into your sequencer can be a daunting task to noobs and the pros as well. There are actually many methods that are promoted on forums and other online spots, but two have come out on top in most debates over and over: tapping them in via dedicated MIDI controllers or using software to draw them in using a visual 'piano roll' editor.
Drawing in drum samples into a piano roll editor is very easy on the eyes and the muscles as well. No physical input or effort is required, and you can even do it while slouching in your chair! It's also very fast to put out, because one can simply click and draw. Getting sounds from your head to the screen and out of the speakers has never really been easier than this, and that's why it's so popular!
Tapping out drum samples using MIDI hardware is the other popular option, but it's very hard for some newcomers to really get the rhythm down and keeping with the tempo. This can be really hard! The tip offered by a lot of pros is to take it slow and start with slow tempos first. You can even use your computer keyboard and assign letters to different notes on the piano editor on the screen, so you can trigger, for example, a kick drum by pressing the K letter on the PC keyboard. Cool, huh?
If you're set on getting dedicated hardware units like the MPK series, you're in for a few advantages over other producers that rely purely on software or mapping their keyboards to drum samples key set. The main advantage is being able to stay away from the screen for prolonged periods! A lot of the MIDI controllers even have stop, start and pause messages (called CC messages) that allow you to control a lot of the main functions of your sampler and control everything from another location a few meters away, for instance.
Each has their disadvantages as well, though. If you're drawing or clicking in the drum samples, you need to be aware of the velocity, otherwise your drums will become stale and lifeless. Also, using the appropriate swing is important, as clicking them in by default will trigger 'snapping' to pre-determined grids.
When playing on drum samples pads, it can be a bit hard to keep overall rhythm to start off with. Also, unless you have very nimble and athletic fingers that are flexible and super fast, you won't be able to generate a lot of intricate patterns. At least not in one go of recording, but most even fail at stacking their patterns properly due to a lack of precise rhythm. What a lot of producers do is build the base track by tapping in the main drum samples - the outline. Once the outline is completed, drawing in the other samples using an on-screen editor seems a good idea.