I'm sure the Ace is a fine tool, and I'm definitely a fan of the spin tester as part of the spine tester.
I'm liking the home made rig I'm currently using: also has a spin tester as the supports (moveable, which helps me isolate bends when straightening), and a set of digital calipers from an auto parts store to measure deflection. Simple to print out the chart that translates the deflection to spine. Been very reliable for me (wood arrows).
Just depends on your preference, the Ace, or Adams, well proven. If you are more of a DIY person, the home built options can also work very well; and cost considerably less if that is part of the decision.