I am thinking of buying one of these for a friend. I have a MotifXS-6 and think it's awesome. Does the MM6 sound good? Especially concerned with Piano sounds.

Tanks.

Ive messed around w/ them in a store. They do have a bunch of decent piano sounds, which Yamaha is known for, but beyond that the sounds, features, and build are lacking. Def not close to your XS. They are priced fairly low though, if you are gonna pay full price, I'd suggest looking into the used realm though. Lots of better choices

Many things sound nice in the MM6. But...

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YOU CAN NOT "PROGRAM" SOUNDS IN THE MM6!!!

MIDI CONFIGURATION IS EXTREMELY LIMITED.

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they should say that on the outside of the box. They called it a synthesizer, but you can't edit squat.

It's a default player, with some baser performance edits you can store, but there is no PATCH EDITING here.

That said, I own one, it's handy. I like the sounds and the sequencer - as very limited as it is - is handy to me as are all the arppegiators.

Can you comment on the key action? Thanks

Despite it's named as MM, and it's regarded as little brother of Motifs little brother (MO-series), it's more near to PSR-series than Motif-series. Get a MOX, they aren't much pricier.

MOX is an excellent digital subtractive synth

I'm no pianist at all, but the keys seem fine to me. plasticy, light, active, kinda solid - not as solid as others. I think they are more solid than my Korg X50 keys. When messing on the MM6, I tend to FORGET the keys in a good way - messing on the X50, I am always conscious of the keys and wondering if I will break them. I would guess the bigger synth versions MO-6 or whatever, have better keys. In fact, I think I messed with one once and they felt better built. The MM6 is bottom of the bucket, but useful in it's way.
It is definitely near the PSR series and thus kinda over priced. I played a PSR recently for $250 and it seemed almost the same as the MM6 minus some features.
I would not usually recommend the MM6 to a friend, unless budget was a concern.... then I might suggest just trying the various PSR instead. less featured, HALF the cost.

I kinda felt ripped off buying the MM6 - half backed midi, no actual synth editing. wasn't expecting that from Yamaha

I think it's one of the better cheap keyboards out there... very very light btw..

I have an MM6 at school, and I've used it quite a few times. My impressions:
- Keyboard: On the cheap side. Playable but not great. No aftertouch. Good-feeling wheels, though.
- Sounds: Rather compressed, leaning on bright quality. A decent variety.
- Portability: Great. I would like to have one for quick reharsals, etc.
- Versatility: Editing is not the MM6's forte. BUT you have four front-panel knobs for quick adjustments of filter, resonance, attack...
- A serious shortcoming: No mono mode (for lead sounds, etc.).
- "Of course", it's powered by a wall wart. Aaaarrgghh.

Can't comment on the arpeggiator/sequencer/pattern player, as I've never used them.