Have used several so far to setup systems for customers as favors without incident. We have also used PowerEdge 750’s for those desiering rackmount variations with equal success.
Great systems, especially at the price point. For 4-12 trunk setups we use the P4 2.8Ghz, 1MB RAM, 2x40GB SATA configurations with great success.
So far the only issue we have had with the model has been the inability to figure out how to leverage the built-in software/hardware RAID of the SATA controller. It appears they have Red Hat Enterprise 3 drivers that should work fine, however our Linux skills are a little lacking in this regard and technically we are running the white box variation of that os (CentOS).
Additionally, I have recently read a couple threads with discussions about the “possible” incompatibility of some of Digium’s T1 cards with the PowerEdge 750 - however, don’t know the merits of that arguement if any - no mention of the SC420 in that thread.