Kevin,
As with most of my footwear, I break them in summiting the mighty Mt. Tabor numerous times, dogs in hand. I probably put on 15-20 hours before heading to the mountains. That's less time than I usually like to on a new boot but I was no worse the wear.
Top answer your question more directly, I had little to no problems during break in, especially after I got the lower lacing dialed in. However, I seem to do really well with La Sportiva's for fit in general.
Now back to farting around with my flippin crampons
-r