The Land Pride dealer (Case Ag dealer who also sells Land Pride) actually recommend the shear bolt model. He doesn't have either in stock so he's not trying to push one he has on the lot.
He didn't seem to think our clay soil around here wouldn't "shear" any bolts as long as you didn't slam the unit into the ground at full speed. He has had issues with "lazy maintenance types"---i.e. = me, not taking the time to adjust the slip clutch each year, and with rain outside or humidity in buildings causing havoc with slip clutches--can be an expensive repair.
I think I'm going the shear pin route--plus it's around $150 to $200 less.
The reverse rotation models really interest me the most. Dealer actually called Land Pride yesterday and they have many forward rotation in stock, but the reverse rotation models are moving off the shelves fast. He had called them for me to check the difference between the RTR1050 and RTR1250 models. If you look at the specs they are practically identical. Only difference is 4 pounds of weight and the RTR1250 only has a 3 year gearbox warranty while the RTR0550 and RTR1050 both have 5 year gearbox warrantys. Land Pride rep said they found a new company for the gearbox's on the 1250 models (new models for 2011) that is costing them much less but still an excellent gearbox. He said the 1250's are selling fast because they have passed their cost savings along to the consumer so the 1250 is the lowest priced unit between the 0550, 1050, and 1250. The 1250 does come with slip clutch only. I'm leaning toward the RTR0550 with shear bolt.