Both are amazing, but made with different goals in mind. Ultima would be better if you are looking mostly for focus and stim free energy, while Hemavol if you want mostly endurance and pump (that is a very generalized way to look at it as they both are very comprehensive in design). They also are very nice to use together.
As for samples Ultima does not have any at the moment (unless I am mistaken), but Hemavol should be available for samples on the iForce site.