filament holder and clip are fine. Still using originals after 2 years never had a problem.

Best add on and the first thing you should print is the ducted fan adaptor to blow air on the prints.

http://www.thingiverse.com/thing:537918

I currently use the mk1 with a simple clip for easy attaching and removing. http://www.thingiverse.com/thing:350649

You'll need 24 volt 40mm fan - cheap from amazon.
I wired mine into the same connector the motherboard fan uses.