I have both and used to own the microtrack also.
I wouldn't recommend any of them.
As I am a 2" analog tape guy, I like how these recorders have warmer sounding recordings than the dat and minidisc recorders I've heard. This may also explain my opinions.
I have used all three of these recorders at the same time, many times. The zoom definitely has better sounding internal mics and this was in many different circumstances. Many people have agreed and some even think my on stage recordings with the zoom's internal mics of instrumental bands sound like soundboard recordings. Alot of people including myself think the internal mics on the zoom sound better than alot of the mics out there.
The edirol's internal mics aren't that bad but have a characteristic of sounding like the mics are recording in cheap thin plastic, which they are.
I was skeptical as I wasn't a fan of zoom guitar effects but there was no question as to the better sounding recordings every time and unanimously, it was from the zoom.
This is by far the best product I have ever used from zoom.
I haven't used mini mics yet but would recommend the edirol for it's size(small) and (from some recordings I have heard) if you are using mini jack microphones except for it's cheap thin plastic construction and overall cheap build. In fact it feels like an empty pack of cigarettes.
I know some people at Leo's Pro Audio in the bay area and they have had a high percentage of the edirol r-09 units being returned. The highest percentage for returns was for the microtrack then the edirol. The zoom hasn't had any returns as it is built much sturdier.
I returned my microtrack as it finished far behind in my audio tests.
The edirol has mini inputs but they seem very cheap and I have seen alot of problems on this site with them also.
The problems with the zoom are the levels are not too easy to adjust quickly and quietly
, it is not totally stealth in size, and if you are using high end mics (which at least you can with the zoom) there are better recorders out there, just not as small as the zoom.
I have used neumann k-184's, u-87's, and akg 414 mics with the zoom and it sounded really great.
I was useing a preamp though. I was later told phantom power is true 48v on the new zoom units, unlike some other recorders. I should try it without an external preamp. The guys at Leo's said the new Zoom units are better than the original ones that came out. That said, I made sure they got me a good one from the newest batch at the time. I wouldn't buy a used one either.
I wouldn't recommend either recorder unless you need it now or have money burning a hole in your pocket because I heard that there are better low price recorders coming out soon. I'm very picky, but then again, I have heard good results with both recorders. I will possibly try the Korg MR-1 next.
But first I am going to venture into mini mic land for the first time. I have purchased mini mics and a preamp from churchaudio. I will try these with the edirol and the zoom first and let you guys know how it works out.
I hope this helped as I have done many, many head to head tests with these units and this site has been very helpful to me with the mini mics. I listened to your recommendations, and more importantly, to your recordings and decided to go with church.
I probably shouldn't say this as I will probably sell it, but I wouldn't buy the edirol used. It's body and input jacks are as fragile as an eggshell and I know how people are, especially with in/out jacks. It makes me cringe when I see it. Along with the problems I have heard, I don't even breathe wrong on mine for fear it will shatter into a million pieces.