I've used both. As software, the programs are very robust.
I have version 5.1 of CPU-Burn-in-Test. it recognizes the processor as "Core 2 Duo" -- probably from information in the BIOS. If you change the stock multiplier of the CPU to a different value, it reports the over-clock CPU setting as if it were the product of the stock multiplier and the chosen external frequency. Several programs need to get on the bandwagon in regard to fixing that inconsistency (from my observations) -- including SnM and Orthos. Version 5.2 (available) should fix that problem, but there should be updates to 5.1 that update it to the current technology options, but I don't know that there are any. It doesn't seem to have an update feature in the program.
It doesn't give the CPU as extensive a work-out as Orthos. It will load up the processor to 95% and the memory to between 50 and 70%, and you can simultaneously test CPU, memory, 2D & 3D graphics, PCI-E bus, etc.
I've used it in preliminary stability tests before running Orthos at various settings. By comparison, I've seen the Passmark program increase CPU temperature to 41C when Orthos will push it to 50C for the same settings.