Went through many of these when selling Benottos and working on many "European" makes during the 80s.
Miche hubs regardless of the model just aren't very reliable.
The races typically hold up - the cones don't - very much like Ofmega and Galli hubs.
I'm not saying toss 'em...just do the following:
1. Pick up good spare cones - from trashed Miche hubs.
2. Get the adjustment just right when riding em.
3. Inspect every 3-6 months...so you can catch bad cones/bearings before damage starts to occur to the races.
I myself would keep a supply of Campy, Shimano, Sansin and Suzue cones so I could substitute in Ofmega, Galli and Miche hubs. Putting quality known-to-be-reliable cones in the three hubs mentioned pretty much made them as good as the "real thing".
The weakest point with entry level and mid-range non-Campy European hubs seemed to be the cones.
Godawful waste in my opinion...go through all the trouble to manufacture nice looking, nicely finished hubs with decent races - and throw it all away with bad cones.
=8-)