I'm with Carole Nash as well and although only used their breakdown cover once, many years ago in the UK, I also know a biker (strangely IAM as well) that had good support when his Triumph broke down big time in Switzerland last year.
As for specific recovery companies, been with the RAC both personally and with the business for a number of years with cars/vans but (thankfully) only one European breakdown although that was sorted quickly with no hassle.