Akai have always been known for a very detailed sound, it's dynamically very rich in the highs and mids, a very sharp sound (so highly prefer on drums by many
Yamaha samplers sound a bit "muffled" although clearly its not the right word here as its not muffled at all just not as detailed as the Akai's sound, dynamically not as rich/full but the sound is much rounder (i.e. low mid & highs are displayed with more harmony though yamha D/A
Roland has a round sound aswell (I studied on a S760) possibility a better more dynamic D/A (not as muffy as yammy) never heard a MW so I can't comment but the S760 sounded very musical had a nice balance between the high mid & lows
that said I personally feel yamaha has the best "analogue" sounding digital filters (so if its the DJ-filter effect your looking for yamha wins although Rolands COSM filter sounds truly excellent for those type of FX by far outperforms all others digital filters (although only one at time globally), Akais filter are more like detailed tools, sharper more precise, if I want an analogue filter FX I'll run it though an analogue filter and resample, although I do have audio of the 4k's filters doing some analogue style damage..
this all has to to with like Deaf-Mute pointed out the quality of components used on the hardware side
if you think about it though: the Motif sounds stellar but the sampling side is no where near the same quality, they didn't sample though the Motif A/D: the sounds are all done & recorded in a top notch recording studio, also when a company can bring out a product that cost 1/3 as much as a 2k and offer 3x as much it tells you corners have been cut (although corp. like Yam and Roland are massif and are running though a massif production chain which leads them to be able to offer better prices
I now I haven’t heard every sampler in the world and I bet their are some very soulful musical sounding sampling engines out there with analogue filters (E3 anyone) but as of now I do think most other samplers sweat when the 24bit balls 96k shaft 4k walks into the locker room
A very good discussion on MPC1000vsRS7000 from an avid RS user/ goes into sound allot aswell
http://data.rs7000.org/forums/showthrea ... eadid=1387