I hear great things about both. I am new to sampling and am wondering which would be best for me. Both seem like pretty basic units. Can anyone explain the pros and cons of both, in beginner's terms? I like the MS because I am used to a keyboard, as I play the piano. But I hear the pads on a sampler are better for beats-- at least they "feel" better. Price is a matter of concern for me.

I will be making mostly psych pop, like Panda Bear or Animal Collective.

Well I hear great things from producers I respect about the MS, it has a cool and quick way of collecting chops or noises from a track by just pressing the key you want the sample on for as long as you want to capture the incoming signal or sample. I do prefer pads for making beats, but thats about where the pads advantage ends. If you add a midi pad control device to the korg MS then you got all the good in one thing, but thats like in the 5-6 bills range and I was barely comfortable spending 300 bucks on a new 303 a week before they went out of production. 404 fits in a back pack and has very creative effects which I like personally but in the end you should try them out if you have a guitar center or sam ash near you.