Korg's sampler is, IMO, by FAR the best sampler in an arranger. It's largest advantage over the T2 is that it will import Akai keymaps and multi-samples. Akai is the format for the largest choice in sample sets, and of especial use because most Akai sets are restricted to usually 32MB or less, unlike many modern sample sets intended for computer use that are GBs in size, utterly impractical to use on a keyboard (other than Neko and MS, etc.)
Unfortunately, as in just about every other sampler that imports Akai, only the samples and keymaps are imported, you are usually on your own with the voice programming. Fortunately, Korg make this fairly easy by allowing you, once you have imported, say, a guitar set, to replace an internal guitar patch with the new multi-sample. Thus, about 75% of the work (or sometimes even more, YMMV) is already done for you, and tweaking is all that's left to do.
Yamaha, on the other hand, do not allow any multi-sample importing other than their own proprietary (and not well supported) format. It's going to be up to you to tediously import each and every sample one by one, and re-create the multi-sample keymaps yourself. Talk about a time waster!
If only Yamaha would allow Akai import (even their top of the line MotifXS only allows .wav and .aiff individual samples, and Yamaha multi samples. Amazing shortsightedness, as Kurzweil, Roland, and many others ALL can read Akai.
Don't forget that sample load times are a big factor if you want to change your sample memory in a live situation..... barely 1MB every two or three (or more!) seconds, so a 15MB load can take up to a minute or so to load up. And add to that that you will DEFINITELY need a UPS power supply, in case of brownout or power disruption (your sample RAM will go poof at the first sign of power loss!).
Best of luck with your sampling goals.....
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An arranger is just a tool. What matters is what you build with it..!