I have one, and even though I'd buy it again, there are some shortcomings that may put you off.
The downside - all the digital mixers in this price range seem to cut your available tracks in half when you go to high sample rates. It's a matter of this being a computer, and only so much processing power. The DM-24 doesn't allow you to assign the 8 busses to the stereo main - the only workaround is running the buss outs back into other inputs and assigning THEM to the mains. As yet, the DM-24 doesn't generate MTC but REQUIRES it to use automation. This will be fixed in the forthcoming V2.0 firmware. The mic pre-s sound very good, but have a linearity problem when recording low level signals with mics - they get very "twitchy" in that part of their rotation. Tascam has no plans to upgrade this on production mixers, but will replace them all if you ship the mixer to them (splitting shipping costs) and pay $200 for the upgrade. If you want to interface the DM-24 with a computer-based DAW at high sample rates, you are limited to one, possibly two interfaces that I know of. The one that has been tested by its maker costs about $1600 to do 8 channels of I/O between the DM-24 and computer. It is made by RME. Tascam has been trying to get SEK'd to respond regarding compatibility of their interfaces with the DM-24 at high sample rates, so far no response. At normal sample rates, you have several other choices of interface so if you don't care about high sample rates, you're set. These are the main downsides to the DM-24, although there are other small ones that usually can be worked around.
The upside - Any other mixer within $3000 of the price should be cowering in the corner, because the DM-24 kicks their ass. The converters are the same as the ones in Tascam's MX-2424 HDR, which has been praised by even some of the analog gurus in Nashville as sounding very good, warm, smooth, etc - the routing flexibility is very good, you can route almost anything to almost anything else internally, and you have the ability to name and save "presets", which are literally everything you can tweak in the mixer. So, the mixer ships with some basic presets, such as "recording", "mixdown", etc, which can either be modified and saved as your own or scratched and done over.
The DM-24 allows MIDI messages to be sent for nearly every control on the surface, so I can be used as a sophisticated control surface for any software that can respond to MIDI messages. For example, Samplitude allows the configuring of up to 16 different MIDI controllers PER TRACK - Cakewalk/Sonar can also be remotely controlled this way.
MMC is sent by the DM-24, but there is almost NO support in any software package yet for that - one workaround I saw was a little applet written by a user and pointed to on the Tascam BBS, that takes MMC commands and converts them to keystroke commands. Sooo, any app that has keystroke commands as alternate to mouse clicks can be MMC controlled. I have yet to try this, only heard about it a few days ago.
Bottom line - The DM-24 costs about $2300, and does everything for Non-ProTools software that Digi's $8500 Mix-24 surface does for ProTools AND MORE. (The PT rig is not an actual mixer) - If you want more, you can cascade two DM-24-s with a kit. There are two slots in the rear of the DM, with plugins for 8 analog in-out, more TDIF (the unit is hardwired with 3 8-channel TDIF connectors and 1 ADAT connector) ADAT I/O and the Cascade kit.
In my case, there are a few things I don't like and a LOT of things I do like. If you want more, you should look at the Yamaha O2R-96 for about $10,000 or
the Yamaha DM2000, for about $20k. Otherwise, no contest... Steve