Actually i had not and now that you bring this into perspective 

1. How many vendors support TRILL ?

2. What are the practical use cases in our market. 

Going back to the original question. What is the preference IS-IS or OSPF. 

As i mentioned earlier at the moment the IGP in use by most networks in our region, with the exception of some networks i know in South Africa, SEACOM and Liquid, is largely due to the technical teams preference over current feature set implementation requirements. But i could be wrong am only basis this from my experience interacting with operators. 

This goes to say that, for smaller to medium sized networks operating in multi-vendor environments, OSPF is more likely to be their preference for interoperability and avoiding to run two different IGPs.  However, for large networks IS-IS is more common, largely because they operate a single vendor or compatible dual-vendor environment.  The interoperability between vendors tends to occasionally suffer from regression bugs - but most of these large operators have a lab thats are  the size of many medium size networks. Therefore, lab testing tends to catch some of the issues well before production deployment.  

FYI and to answer your earlier question SEACOM are running a BGP free core which runs entirely on IS-IS and MPLS.  They have specific use cases and you may want to speak to Mark Tinka or Simon Mayoye about their IS-IS implementation. 

 

Have a great day.