USB Mod vs. INTERNAL mod

[jungleq]

I'm looking to purchase a mod chip and want some information. I have to do the soldering myself because i don't trust anyone around here to do it (Canada). Obviously the choice for me would be the usb mod but i want to know the differences between the two. If i buy the usb mod will i be screwed for some backups? Any info. would help. I'd love to hear from people that have used both or have one or the other.

Thanks