PowerPC is almost always dest,src,src, except in the case of a store, where it's src,dest,dest. OTOH, SPARC is almost always src,src,dest except for compare/exchange. Fun, huh?
I think the argument about order of source and destination is pointless - most people argue for the form they learn with. What does bother me is order of subtractions. I think PowerPC gets this right:
You think "subtract from immediate and carry", so the operation is IMM16 - rA => rT. And then there's:
Where you think "subtract", and the operation is rA - rB => rT. But PICmicro gets it wrong. Look at this:
Now you would think, from the mnemonic, that it's "subtract literal from w", but it actually does the opposite. The operation is IMM8 - w => w. The designer probably thought something like "subtract: literal - w", but it's still ambiguous and/or misleading.
But big-Endian is the one true way - it's far easier to read in a debugger, and you find bugs where a person does things like *(INT32*)ptr8 when they mean (INT32)*ptr8 much faster, as that doesn't come close to working on a big-Endian system.