I am looking into building with SIP's and possibly becoming an installer after I build. Today I was talking with a builder that uses me as a sub- contractor and he said attaching some , or most exteriors  to SIP's is a problem. He said he felt that the longevity of the exteriors would be compromised over time due to it only being attached to OSB and really nothing else. Can anybody offer a positive counter to this opinion?
Thanks.

We mostly build with steel SIPs but I believe your builder's opinion is not based on any knoledge of failures over SIPs, The OSB is laminated over a solid core of EPS or urethane. providing a constant solid surface as opposed to an attchment @ every stud @ 16 oc.
One thing you do not see on a SIPs structure is the truss line @ 24" due to sagging roof sheathing.

You can use most any exterior for OSB SIPs if not all. And there would be documented failures or warnings from manufacturers if there was a liability for them. There are sometimes issues such as blind nailing hardi that should be avoided, but you should not have problems over time. And try to go with stucco as the straight walls with fewer breaks will give you a better product and save your sub time. Maybe you will get a break after the savings are realized. The only blemish in the industry appears to be where faulty installation created issues such as in the roof in Juneau or in cases like the one in Dallas where the factory going out of business shipped panels marked bad. There have even been methods for suggesting installations such as half log siding using thicker osb. And you can always use furring strips. See the Bill Chaleff article on baloon framing to see what OSB can do.