Feature:
In the beginning, the 4 sequencer wasn't that bad. Now it's a pain, but for the money, you can work with it. Especially if you're using multitrack software. The biggest headache is when too many voices are played at the same time. It stops your larger samples from playing.

Quality:
I'd have to say I'm a little worried about dropping it because of its weight, but I haven't had any mechanical problems at all.

Value:
For the money, it's worth it. If you have the money, splurge on the mpc, it'll give you more breathing room.

Desirability:
I was really intrigued by the dimension beam which is really cool and you can come up with some crazy runs. Add some reverb and it sounds like an electric guitar!

Sound:
Make sure you sample from a good audio source. Don't sample through bad cables or your samples will sound crappy.

Ease of Use:
It's really easy to use, especially sampling. I like how quickly you can jump into recording a beat. With great sounds you can come up with great music.

Support:
Very poor. They barely have anything on the web.

Feature:
The onboard memory is small, so you will definitely need to add a Compact Flash Card (none provided). There are more effects than I know what to do with (yet). The D-Beam is fun but I haven't found any practical recording application (this is geared toward live performance which I do not do). USB connectivity makes adding samples pretty easy. Cannot find a way to adjust volume of individual tracks in the 4-track sequencer. I don't use the software component much (yet). I bought a hardware component because I don't like composing music at a computer. Features like Autochop, Time Sync, velocity sensitive pads, USB connectivity, MIDI Sync, 45 effects, 3 effects processors, companion software... make this a very complete package. The single biggest drawback is the 8 voice polyphony (I expand on this in the Value section).

Quality:
I have had no issues in the few weeks I have had it. The OS has been solid with only one malfunction (you must shutdown the USB connection from the comuter or it will hang). It sits on a desk in my home studio. If I took it out I would purchase a good case and be careful as its mostly plastic.

Value:
As an introductory piece this is worth every penny but for all in one music production it falls short. I bought this as a drum machine that I could load whatever sounds I wanted into. For that purpose the SP606 is more than enough. I found myself making types of music I had not anticipated. And here is where I ran into some trouble. Most of the samples I use are stereo. This reduces the polyphony to 4 voices. So a kick drum and a symbol sounding at the same time (common) now leaves me with 2. A bass synth and a hi hat leave me with 0. I will probably resample to mono to get around this but if I really wanted to keep the stereo sound I would be stuck. That being said I also have a mutitrack recorder which can always be used to give me all the polyphony I would ever need.

Desirability:
It looks very sharp (the SP 505 looked like a toy and was considered one by many, the change in look was dramatic).

Sound:
This unit only plays back what you put in. So, Garbage in Garbage out. Quality in Quality out. If you put CD quality samples in you resulting music will be CD quality.

Support:
Good luck... Roland is notorious for poor customer service. The have virtually nothing on their website (nothing useful anyway) and are closed by the time I get home from work. My biggest problem with them is that when I need them they are not available.

Overall:
I am primarily a guitar player that was looking for something to add percussion to my recordings. I bought the SP606 because I knew I would never get bored of the sounds because I could easily change them. It has not failed to meet my needs. I have even found myself creating music on this alone. The built in sound are not very useful. They consume the first 4 pad banks. These are among the 16 easiest to reach. So if you don't use them you have 12 easy to reach pad banks (there are more but then you have to scroll through a list rather than just selecting by pressing a designated pad).

Feature:
4 TRACKS IS GREAT (wish it was 6 or 8 tracks). FX'S IS GREAT DELAY, TAPE ECHO, ISOLATOR, AND EQ IS WHAT I USE THE MOST.

Quality:
IT'S A LITTLE LIGHT BUT THAT'S OK

Value:
I THINK IT'S GREAT FOR THE PRICE. IF YOU CAN'T GET A MPC THAN GO WITH A ROLAND THE BEST IN IT'S PRICE RANGE

Sound:
THE SOUND IS GOOD . IF YOU SAMPLE FROM A GOOD SOURCE, YOUR TRACKS WILL COME OUT FINE. BUT DOES NOT SOUND AS GOOD AS A MPC.

Support:
HAVE NOT USE THEM YET

Overall:
I HAVE HAD MINE FOR ALMOST A YEAR NOW, AND I ALWAYS FIND NEW WAYS OF MAKING A BEAT ON THERE.