On Tue, 19 Jan 2010, Mojca Miklavec wrote:

>> This can be a bit disturbing for experienced TeX users.
>
> - The deciding moment when some of these ugly tricks have been thrown
> away was when we realized that if you do add those tricks, there is no
> way to print the grave accent. (Grave accent will be automatically
> converted to the same "comma" that you get in quotation marks.)

This is really important when your are trying to typeset source code. 
Simple things like

   a = 'string'
   b = `some system command`

gets printed as

   a = ‛string‛
   b = ‘some system command‘

Depending on which font you are using, this change can be very confusing.

Aditya