As of today, Case Construction is the only manufacturer to make the over-center boom backhoe loaders (pull the boom lever, and when the boom touches the 90 degree mark, push the boom lever to lock the backhoe into transport mode so it doesn't bounce so much). But way back then, Caterpillar also made over-center booms too. Here's the remnants I managed to "dig up": I don't like the banana-shaped boom that Deere and Cat makes, because it looks like someone was tugging on some sturdy object with the backhoe and overtime, that caused the boom to bend and deform. And also, Deere's backhoe extendahoes tend to drift down overtime regardless if the machine is idling, running (with the loader), or turned off.
Do their extendahoe models not have a lockout pin? My Ford 555D does.
That's a good question, and I have no answer. The over center latching booms also tucked the backhoe closer to the parent machine, making less tail dimension. And, unless I recall incorrectly, since they tuck up tighter you could swing the backhoe fully left of right and it would still be inside the tucked outriggers making less tail weight for less front axle bounce during roading.