I've shot one, but it's been a while. One thing I've learned is there can be a world of difference in a bow that is tuned for you vs. one that isn't.
I've never seen a bow that has zero shock. A lot of it is perception--some folks say a "brand X" bow has no shock to them when the same bow rattles my teeth.
For a bow to truly have no shock, it would have to be 100% efficient at transferring all the limb's energy to the arrow. That bow doesn't exist. Energy that doesn't go into the arrow resonates down the limb to the riser, and that's where hand shock comes from.
Some have much less by design, some mask it well with a heavy riser, etc.
Anyhow...the only way to really know if you'll like the Tomahawk is by giving it a try. I'm not sure if 3 Rivers has a "try before you buy" program--it would be worth a phone call to find out