A few thoughts on the announcement: http://reviews.photographyreview.com...t-dsmc-system/

It's an announcement.
Well in advance of actually being able to order one, let alone take delivery.
Availability is estimated in 2009 but the Scarlet has been the subject of a redesign to get to this announcement and delayed from its initial plan as a result.
They're quite open about it, the announcement page says "Prices, Specifications and Delivery dates are subject to drastic changes. Count on it and you won't be disappointed" and while you can hope for cheaper and sooner, I don't think that's likely.
The current camera, the RED ONE is announced as being off back-order and available for purchase.

It requires post processing of the video.
You can't compare it to a Digital Video SLR (DVSLR) which shoots an immediately playable format. The wavelet compressed raw file format REDCODE 42 requires a large amount of processing power to turn it into a non linear editing format.
RED recommends the current top end configuration of a MacPro with 8 cores, fast RAID 0 striped drives and a minimum of 4 gigabytes of RAM if you plan on editing 2K or larger QuickTime reference movies.
This is like the shift from shooting JPG to shooting RAW for us, not many people are doing it and it involves good, fast, post-processing software on fairly powerful computers to move the workflow.

It's heavy.
If you don't think the "brain" consisting of sensor, electronics and lens mount weighs enough (under 3lbs but by how much?) add on the grip and battery (yes they are extra) and a storage module and an electronic viewfinder or LCD screen.
Well I suppose it's relative, heavy for a DSLR is light for a professional video camera.

EVF.
There are no specifications for the Scarlet EVF yet, but the RED ONE EVF is 1280x848 progressive display.

Lenses for the job.
If you look in detail at the lens section, you can see the little things that separate the RED video lenses from our still lenses. Teeth on the focus ring and defined rotation to focus so that it can be driven externally, compared to a Canon USM lens where there's just a rubber ring which is sort of loosely related to focus. Accurate focus markings are required too. Same for aperture.
Talking to a videographer at a corporate event I was shooting stills for, who's shot with RED ONE and also DSLR, said he can't see how you can properly pull focus on a DSLR lens.
I think that's why there are RED lenses for video, and adapters for Nikon and Canon for still allow current DSLR users to migrate.

It's a professional video system.
From the RED website, before the announcement "We are not interested at all in consumer cameras at this point... maybe someday, but not now. Everything we release for the next few years will be professional, ground-breaking and interesting."
Yet Scarlet accepts existing cinematographic lenses on the PL mount, builds on current standards for accessory rails, uses follow-focus, mattes boxes etc. It has to, so it fits into the existing infrastructure.
I don't think you'll see any of that on a Canon 5DmkII or Nikon D90.

Audio.
The RED ONE camera has four audio inputs with XLR connectors, the I/O module for Scarlet looks similar but only two XLR, EPIC is promised to be even more than the current ONE.
Compare that to the Nikon D90 that has no microphone input at all, and the Canon 5DmkII that has a single input.