I love my Durango's, they are very well built and the team/set up data, website etc are all top notch!
I do agree on your points about the kit delays, a victim of their own success. Hang in there if you have one on order, its worth the wait.
As for spares, they dont really break, on my 410 I have not broken a single part in 3 years (racing every week), I'v worn things out!
I havent had an issue with spares, MB have most of the parts I will ever need.
http://www.rccarshop.co.uk/