You're looking for the workstation that best fits you.., so off the top I'll say the X-50 probably won't please you for the use as a "workstation". Although the X-50 has some great Korg sounds.., what it lacks is the ability function (on it's own) as a workstation. The X-50 is a performance synth with no sequencer.. Any sequencing done on the unit will need to be done via a software app or external hardware sequencer.
The MM6... This is ABSOLUTELY not a workstation.. DO NOT fall into the bullcrap HYPE that Yamaha has dished out on this unit. The Yamaha MM6.., IS NOT a workstation. This keyboard is so limited in many functions that I can't believe Yamaha even calls it a synth. A synth would at least have one of the most basic and common features on a synth which is PORTAMENTO.., the MM6 does not have this feature. At the CORE the MM6 is nothing more than a Yamaha PSR.., without speakers. It's an arranger keyboard.., DON'T LET ANYONE HERE try to tell you different. I've persnally got confirmation from Yamaha that the MM6 is made in the EXACT same factory as the PSR line. Also the patterns on the MM6 are not patterns.., they're styles that utilize auto accomp. Yamaha called them patterns so the board would not be associated with arranger keyboards-nothing more than just a marketing gimick. The voice editing is a joke. Its got the same low quality control knobs from the DJX series..., AND the MM6 has NO user voice storage. Every tweek you make has to be stored into a "Performance" This is a classic arranger keyboard feature. The sequencer on the MM6 is a joke.., its in NO WAY a real sequencer. It's 8 tracks (strickly linear) with NO loop recording and NO post song editing. To do any real recording with the MM6 you have to use the software that ships with it..., BUT that again brings up another HUGE problem. The moment you start stacking tracks it won't take long to blow the poly out as the MM6's poly is only 32 notes (yet another classic low end arranger keyboard feature of Yamaha's) It may have some Motif Flavored sounds, but you'll without a doubt find quite a few of the lower quality sounds from the PSR line as well. It's just not worth the money IMO..., and if you want that dedicated workstation this board will fall seriously short.
Now the Korg Trinity, Fantom XA, and the Triton LE are ALL workstations. They have full synth functions with indepth voice editing.., offer sample loadings, and fully loaded sequencers. I think any of those three would make you happy .... HOWEVER.., of those three the TRINTIY would be considered quite dated by today's standards. Taking into consideration of up to date specs in terms of sound quality and features (and the most bang for your buck).., the Fantom XA would stand out of all the budget (little brother workstations) the Fantom XA is the closet thing to its bigger brother you can find. It has the same 128 note poly, allows voice expansion via expansion boards, the sampler comes STANDARD (the Triton LE's sampler has to ordered separately) The XA is truely a baby Fantom X. The others have severly stripped their budget models down.
Also the S-500 is not a workstation either... It actually shares quite a few things in common with the MM6 (obvious thing is it too is an arranger keyboard..., don't get me wrong arrangers are not bad keyboards as they can be very useful writing tools, but the S-500 is not). The S-500 again has limited 32 note poly.., absolutely NO voice editing options, the same very limited 8 track sequencer from the MM6 with no loop recording or post song editing..., its doesn't even have basic Midi In/Out jacks (only USB). Again with the S-500 any real recording will need to be done via software..., which then you'll have to find the instrument defs for it or write them yourself..., and once you start stacking tracks on it again it won't take long to blow the poly out.
Squeak
**Also VERY IMPORTANT..., if you like to write and play hip hop, and electronica DO NOT BUY AN ARRANGER KEYBOARD. Some of the upper end pro arranger are extremely nice. They're some of the best keyboards on the market IMO..., BUT arranger keyboards are NOT voiced for modern styles of electronica. They lack the sound set for this music. They also DO NOT have the preset drum kit to "properly" match the styles. Depending on how you like to record..., the arranger keyboards recording platform IS NOT user-friendly for electronica. What's very popular in these styles is having gear that allows you to "pattern chain". The arrangers sequencers aren't bad, but are not very intuitive for writing hip hop, club, dance, ect. Reason is you have to create a STYLE.., it's not hard but creating a user style has restrictions that you have stay within so that the style will work properly with the auto accomp feature. Again.., arrangers are very nice keyboards (especially the pro models), but these keyboards are really designed for the OMB (One Man Band).., who play more traditional and classic styles of music such as jazz, big band, rock, blues, country, gospel, and so on.
[This message has been edited by squeak_D (edited 09-12-2008).]
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GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.