Personally, I would not use a rack case of less than 4U.
I have followed the Coyote systems since they first appeared. They may be just the thing a particular person wants. I do not find them attractive. A well-built, generic 4U machine has so many more options available. One can upgrade parts easier, to get a longer life from a given setup. One can use more generic parts, reducing end costs without reducing computing power. One can mount more drives with fewer cooling issues.
Since I do a fair amount of live work, and am always looking to reduce the weight and size of my rig, I am certainly not one to oppose small and smart machines. I think these are small and smart. I just wonder about their ultimate financial value to the end user, and how their costs will figure in over the long haul. Case in point, I bought a 4U turnkey system from now-defunct SoundChaser in December 1999. It is still operating today. Every part, except the keyboard and trackball, has been upgraded more than once. Yet, each time with the maximum possible economy. It has been a remarkably good deal spread out over those five years. My cost of computing for that machine has been very reasonable.
I do not see the same cost/performance benefits for these smaller, necessarily more proprietary designs. So, I think the only thing that speaks for them is an absolute necessity to come in at under 4U in a rack. Unless one has a specific physical disability or some extremely compelling reason for desiring it, a less-than-4U solution is going to bring potentially more negative baggage with it than is worthwhile.
I just spent a lot of time researching this stuff because I have to go to overseas for a gig. Bruce must be more buff than me because the weight of the 4Us turned me off, although I agree they would be the best size for rackmount.Then I looked at building a 2u system, found the exact same case as coyote sys, but was worried about heat and noise, so I did some research on the Silent PC forums, where they basically told me there was almost no way to make something that size quiet. So then I got a headache. The silent PC guys recommended I look at some of the SFF (mini pc's) and recommended a couple that are quiet. I finally got a Shuttle SB81P which has gigabit LAN, PCI slot and room for 3 drives. And I can get a little carry bag and take it on the plane. I think it will be better than a laptop..although I haven't built it yet.
A friend of mine owns four (he's travelling and forgot the url, so I had to ask)...bu he's very unlikely to settle for a noisy unreliable machine!
He has now scored two of the biggest blockbusters of the last year with his units, and only had extremely good things to say about them (both on the reliability as well as hardware fronts) hugely powerful, never had a polyphony limitation, very silent etc.
I am a little surprised at most of the points made about 4u advantages (I'm a composer, not a computer-man...so updating elements myself is out) as I own a Turnkey/Carillon 4u myself , solely for Giga, and they are very well rated as music PCs, but their reliability is very average. (I mean from a system/OS point of view, not Giga)
Furthemore, when I inquired with Turnkey about updating the machine - as well as some of my tech-friends - I was actively discouraged to do so as the heat generated by more powerful processors requires so much peripheral updating (mother board or other elements...etc) that I should buy a new machine in order to be guaranteed a real reliable update...and not least because, unless I built my own, the prices are very similar!
I am not in a "money no object" situation, and I have all the respect in the world for technical advice posted on these threads, including this one, but based on my experience with 4u PCs, I fail to see the huge advantages of the 4u options if one is not planning on doing some hardware work himself...
...and unless something specific could be pointed to as being a real experienced downside of these smaller machines...
Well, not owning one I can't say but I can say the guy who runs this company "Killerbobjr" rocks. He has always rocked when it comes to computers and music.
If your friend is having such wonderful success and none of the comments are really knocking the machines, I'd say go for it.
One thing can be pointed out, when someone who knows how to make a music machine makes it, it will last a few years. I own the same Soundchaser lunchbox system that I bought four years ago running Giga 2. Really no problems! I am going to upgrade it in a few weeks but again I'm going thru someone who knows how to make the box fast and silent and reliable.
I'd say get the Coyote box and when time comes to upgrade it, Coyote might be the company that helps you. This way you're just composing the music and not juggling screw drivers.