which chip program is best?

does anybody know what the differences are between all the kinds of chipped ECUS you can mod with?

Skunk2, GUDE, Spoon, JUN, Mugen, etc.

which is best for switching from OBD0 to OBD1 with a conversion jumper harness???

this would be on a '90 LS B18A NON-VTEC

all advice appreciated whether positive or negative