Media Composer 3 is actually pretty cool compared to 2.8 but it isn't going to be cheap for us. I have been nagging about a special upgrade price for us but no luck yet. the product we need is MC3 Mojo DX or MC3 Nitris DX.
Mojo DX with MC software is $10,000.00
Nitris DX with MC software is $15,000.00
Mojo DX is like the Xena board in the fact that it pretty much is just a I/O device. It is a box and not a card but it pretty much just pumps I/O the video that MC can do on your system in RT. You can capture to DnxHD files which are much smaller then uncompressed HD but you need at least an 8 core to do so.
Nitris DX has acceleration sort of like the Matrox Axio boards for Premiere. It has DnxHd built into the box so you get better performance from MC. This is one step above what we have with Chrome Xe.
If you can afford it and money is no object then MC3/Mojo DX is a great way to go. Sadly not all of us have that kind of cash sitting around. Depending on the work stations you have right now you may have to upgrade the video card when you move to MC. MC seems to like to work best with Nvidia Qudro cards. Other cards work but they are not supported and they may or may not cause issues. Like with Liquid the video card makes a huge deal in MC3 and if the video card is not a good fit it can really cause a lot of problems. You gotta love gpu enhanced software. It is really awesome at what it does but if the gpu gets even slightly off it causes so many problems.
You really have to ask yourself however is Chrome Xe does everything you need it to do right now. If it does then I see no reason to upgrade right now unless we Xe users get a better deal. For the huge cost investment you will gain a lot in terms of RT performance and rendering but in terms of raw editing features you will not gain a whole lot. Liquid Chrome Xe is already a very capable system and I see it working well for at least 3 or 4 years yet and maybe even longer. I tend to do most of my graphics in After Effects or 3D Studio Max so to me a NLE is just mostly to cut my video and Xe does this very well. The only down side to Xe is the render time for final exporting but for us uncompressed goes pretty fast anyway so it isn't as much of an issue as it is for HDV users.