OK. I have been using the 24d tonight and today all day.
First off, the preamps are some of the best built in pres Ive heard on an interface. They have alot of beef and bottom end to them. They almost sound like transformer based preamps. They have a great clip to them too. When you drive them they have a nice soft clip and not just that harsh distortion you usually hear.
The reverb and comp/eq built in sound really excellent. The interface for them is a bit quirky and hard to get used to. But it lets you apply the signal to the incoming signal or route it through a send/return from your software. And you can, for example, apply the reverb to a vocal thru the pre so the vocalist can hear reverb, but the track records dry. An excellent feature that you're not going to find in other units. The effects work thru the unit itself and are not plugins.
The built in mixer are good and it can do very low latency recording. I can get down to a 1.5ms setting even on a modest setup. One thing to watch will be the FW driver interface itself. In testing, it worked with one FW chipset ok, but not with another. These were both laptop setups. With a decent dedicated firewire card you will be fine, but just beware of the combo cards found on most laptops.
For $500 its a pretty good choice for someone who wants 2 good preamps, very good effects that dont weigh on your cpu, and has an external converter you can hook up thru adat. The Konnect8, for $200 less, is very limiting with only 4 total ins and no built in TC effects. But it uses the same pre amps, which are above lots of others in its field.