I've started a combine collection which does include an old Massey 90, JD 55, IH 151, and Case 600.   We also have a late MF 510 too.   I like all of these combines but they have some interesting differences.  You paid a price for that low profile design with everything being hard to access and hard to work on.  Just to check to the oil you have to squeeze yourself between the wheel and feederhouse.  I can take two steps up the ladder on the 55, reach over to the engine, and pull the dip stick.  Can't imagine how fun it was to do a engine tuneup on a Massey.  Everything on the 55, 600, and 151 are on the sides and easy to get too.  Only thing I liked about the Massey design was the easy access to the cylinder.  Reason Massey was so popular is cause they got a head start on everyone with the Harvest Brigade and the publicity it got.  The first SP combine a lot of farmers saw was a Massey and that is what they bought including us.  And Case combines had everything that Massey had before Massey except the turret auger.  They were not that far ahead of everyone.