okay.
I'm going to compare the MS2k to the radias.
I'll explain the difference with the R3, MK, etc afterwards..
Radias has selectable (cross, waveform, unison, VPM) modulation for OSC1 / MS2k has a fixed (waveform for saw & pulse, cross for sine, etc) modulation setting for each OSC1 wave
OSC 2 are virtually the same on both
Radias has two multimode filters / MS2k has one
one Radias filter has continuously variable slope / MS2k has fixed state filter
Radias has routing inside filter section for velocity / MS2k has to use virtual patch
Radias has driving waveshaper placeable before or after the filter, with variable drive/depth parameter / MS2k has on/off drive after filter
Radias has 6 modulation slots / MS2k has four
Radias has two assignable IFX for each timbre (based on KP/M3 series effects with many parameters) / MS2k has modulation and delay effect for whole program
Radias has EQ per timbre / MS2k has EQ for whole program
Radias has one MFX / MS2k has no MFX
Radias and MS2k have three modulation step sequencers
Radias has two step sequencers, and an arpeggiator with mute steps, and velocity and gate time per step / MS2k has arpeggiator with no mute steps and no other parameters (you have to use MOD seq for this)
Radias and MS2k have two LFOs
Radias has three EGs with four different curves, plus parameters to control velocity sensivity (both in level and time), and keytracking of EGs / MS2k has two static EGs
Radias has four timbres and 24 note polyphony / MS2k has two timbres max with four note poly (reduced to two in dual poly mode, virtually unplayable for layered poly sounds)
Radias has PCM samples e.g. string, bass guitar, acoustic, EP, etc along with DWGS waveforms/ MS2k only has DWGS waveforms
note that this only covers differences and similarities are left out, naturally the Radias wins out on most of the differences...
Now, the MicroKorg is virtually identical to the MS2k, except it has no modulation sequencers, but it does have muteable arp steps.
The R3 and MKxl don't have the step sequencers (but at least the R3 has the mod sequencers, not sure about the XL), also they have mainly DWGS and not so many PCM waves, although i'm led to believe that the XL also includes a very basic piano PCM wave.
The R3 and XL only have two timbres (like the MK/MS2k) but still have per timbre FX and EQ. they also both have 8 note poly (so still 4 note with two timbres, which can still play chords with layered sounds

)
The XL doesn't have any reverb effects, mainly delay and modulation effects (i think something like 15 in total?), like the MS2k, but you can still pick any combination from a selection of effects rather than being limited to the modulation>delay setup on the MS2k.
if I get round to it i'll do a complete table in excel or something