While you may not be in SDI now, it may make a lot of sense to prep your infrastructure (cabling, routing, connections, etc.) for SDI and most important HD-SDI. Since you are looking at composite options, they are out there, but are becoming scarce. Consider taking a hard look at converting those signals rather than buying a server with a more limited life span (and less quality output). Of course it may not matter on those issues, but...
I have both used (currently have a 360 ImageServer 2000 in one of my headends/studio control and beta testing another from TRMS), installed, supported, and recommend both of those servers/companies. However, I do suggest taking a look at your critical needs as both of those server lines (whether HD or SD) have some significant differences depending on the model.
For example, 360 focused there servers as deck replacements - simple, reliable, cost-effective and basically you just pulled your deck out and shoved in the server, tweaked some serial controls/cabling and you were on your way.
TRMS is part of a larger automation system with serial and IP based protocols and a larger file codec supported playback options.