Depends on how you ride. Rumbux does not attach to the engine casing and Altrider does.
I have Rumbux and do not regret. Many more will say the same about Altrider.
Both are VERY good and both will protect your bike from your average carnage, but the Rumbux goes just a tad farther to place the impact on the frame rather than the sump.
Plus... Eric V is great to deal with!!! ::008::