Works great for me.
I just switched from inline attachments to thumbnails, so this seemed like a logical step too. Lets just say anything that uses less server resources is a huge plus in my book.
Added this to my .htaccess to prevent .attach viewing on an Apache server. Seems to work fine.
Code:
RewriteCond %{REQUEST_FILENAME} \.attach [NC]
RewriteRule ^.* - [F,L]
Thanks for the modification, Vitaly!