We are moving to version 10.1.500 on Monday.
Does anyone know if there is a way to do a Selective Mass Replace/Delete?
Is there a way to select where the replacements happen?
Does anyone else use some other method to do this type of change (DMT, manual, etc.)?
mass replace / delete of what? Need more nouns 
Sorry, Rob .
Pretty frequently, we need to replace a purchased material in a method, but only when it is used on certain groups of products.
It is a 1-to-1 direct replacement, but the part number changes.
Is that a little better?
DMT would be my tool of choice for this.
You can always import the BO’s and write something custom too. I do that all the time in a program called LINQPad. It’s DMT, but without any limitations. and can be used for all kinds of programming
Amber,
I would concur with Matt, probably the most efficient low cost of entry tool would be DMT. There are always multiple roads to the airport but each comes with its own cost of entry. Database integrity, your maintenance agreements (custom code that circumvents business logic i.e. ‘no limitations’), ability to write/develop in C# etc… You asked about a better way, can you qualify what you mean by better? Prevailing opinion on here most likely would run (going out on a limb here) that DMT is the better way for the vast majority to tackle a task like you described.