I have a Microtrack, and like it very much. The phantom power is 30 volts, not 12. It will power all but the most obscure mics. The very first ones out of the gate last June did have some issues, so there was a firmware upgrade. Mine was upgraded before it shipped.
This is a fave of tapers out there, among other machines. Its small size makes it a terrific tool that can be Velcro'd to the side of just about anything, including a producers vest with a Velcro shoulder. I haven't worked with the Marantz, but know several people who like it. It's a frequent topic of discussion at DVInfo.net and other pro audio websites, so it's easy to search out.

[edit] Just found this review where the Microtrack was demonstrated to have had a lower noise floor than the Marantz. If that's the case, the Marantz must be noisy, because the Microtrack is a little noisy with dynamic mics and the gains cranked.

I tried the Marantz, thought it was nice to work with, but unusable because of the noisy micpres.

If you're after a good and expensive field mixer this might be worth a look:
http://www.cevl.com/4mix.html

Bob.

Bob,

That thing looked very cool!

Great design philosophy, should sound better than many other standard boxes, and location recordists will appreciate that it will even survive being run over by a car without breaking a sweat...

Bob's link again.

Anybody try the Fostex MR8HD yet?

It's hard drive technology, but looks really attractive at a 399 street price from BSW.

At that price you'd have to wonder and it's only 16/44.1 which might be OK but really it's target at wannabe musicians, I think you'll find the mic preamps to be pretty hohum. Bear in mind that's about the price of a single mid range mic.
Bob.

I have the Marantz PMD660 and it’s great with the proper condenser mic but it is a bit noisy when used with Dynamic mics. (but the documentation explains this and recommends that you not use dynamic mics with it for best results) Also the mic pad is noisy for some reason. I use it with my AT897 and the recordings are excellent. I’ve also used it coming direct out of a mixing desk and that is pristine as well. So it performs extremely well for my intent. If, however, I try and use my AT4033 (which is hotter than the AT897) I have to use the pad and then it gets noisy. I would have to pick up an in-line pad if I wanted to use the AT4033 with it.

So I am very happy with it but you have to understand its limitations. I bought it instead of the MicroTrack because I wanted XLR, 48v phantom power, replaceable batteries, mono record mode, big volume knob, large easy to read audio meters. The MicroTrack has none of these features.

There is also a review of the PMD660 on the same site that Spot gave you the link to the MicroTrack. They gave it a favorable review. You can also listen to recordings made on it with different mics from that page and hear for yourself. You really need to listen to the recordings. They are your best guide and after hearing them I promptly purchased the unit.

~jr

Bob, it is 44.1/16, and I'm sure you are right about the user base, but it might be a good audio device for semi-pro and backup audio use. Price points on quality stuff is getting better and better. Here's the BSW link if you are interested at all:

http://www.bswusa.com/proditem.asp?item=MR8HD

and here are some of the specs form the Fostex website. I haven't used any Fostex products, butr a co-worker has in the past and said it was pretty good bang for the buck stuff.

RECORDING/REPRODUCTION
Recording Medium 3.5 inch, hard disk (E-IDE type)
Approx. Recording Time 943 minutes (8-track on 40GB)
Recording Format FAT32
Sampling Frequency 44.1 kHz
Quantization 16-bit linear (non-compression)
A/D Converter 24-bit Delta-Sigma
D/A Converter 24-bit Delta-Sigma
No. of Recording Tracks 8 tracks maximum
No. of Simultaneous Rec. 4 tracks
Recording/Reproduction Frequency 20 Hz - 20 kHz
Dynamic Range 88dB or more (typical)
T.H.D. 0.05% or less (typical)
INPUTS/OUTPUTS
Analog In (4ch)
Connector

Input Level
Input Impedance
- XLR-3-31 type (Pin2:hot) and ø 6mm TRS phone
- 48dBV (MIC) - +4dBV (LINE)
- 1.5k ohm or more (MIC/BAL)
- 40k ohm or more (LINE/UNBAL)
- 500k ohm or more (GUITAR/UNBAL)
Stereo Out (L,R)
Connector
Output Level
Load Impedance
- ø 6mm stereo phone
- -10dBV (unbalance)
- 10k ohm or more
Headphones
Connector
Max Output
Load Impedance
- 2 x ø 6mm stereo phone
- 20mW or more (@32 ohm)
- 16 ohm or more
MIDI Out
Connector
Format
- DIN 5 Pin
- MIDI Standard
Foot Switch
Connector
Level
- ø 6mm phone
- TTL Level
Digital Out
Connector
Level
- Optical
- IEC 60958 (S/P DIF) 44.1kHz
Digital Out
Connector
- B type (data save/load controlled from PC)
General
Dimensions 312(W) x 264(D) x 88(H) mm
Weight Approx. 3 kgs
Power Requirement 100V - 230V, 50/60Hz

Just discovered Marantz 660 has been chosen as the new field recorder for Canadian Broadcasting Corporation radio reporters.
They will replace MD machines as they die.
I suspect many of the mini disc machines will meet with a premature and untimely death under the wheels of CBC vehicles and swivel chairs!
XLR inputs one of main deciding factors.
More rugged.

Note Dynamic range is 88dB, top end end can manage over 120dB although that's at 24 bit, still 16bit is a lot more capable than that 88dB.
Bob.