I am currently in North America after being in the EU & Iceland with the weestrom on VIC plates along for the ride. Based on my experience, you need to split the insurance into two types:
Travel insurance - this covers you for injury/illness, lost luggage, cancelled flights etc. I insured through Travel Insurance - Save for your Holiday with Travel Insurance Direct
(who are a front for Allianz) at AU$526 for 6 months global travel. They only insure Aust citizens and residents. I picked this insurer as they only exclude coverage if you "ride a motorcycle without a licence that is valid in the relevant country". Many policies exclude injuries/medical costs from motorbike travel all together. This effectively provides my own personal injury insurance.
Motorbike insurance - which varies by country/region. Each place has its own nuances in relation to the way it works and it is possibly easiest to consider the typical components:
# third party injury (aka liability) - covers the costs of other parties medical costs if you hit them
# third party property (aka liability) - covers the costs of other parties repair costs if you hit them
# fire and theft (aka comprehensive) - covers the cost of the bike being stolen
# personal property (aka collision) - covers the costs of fixing your own bike when you crash
# personal injury - covers the cost of your own medical costs in an accident
The terms in brackets refer to the US equivalents to Australian terms, as it is the jargon that can be really confusing - a mix of different names for the same concept and the injury components being impacted by state regulation. You will often find that having insurance for the injury components is mandatory in Western countries. In addition, the word comprehensive can easily have different meanings - in Australia it typically refers to a policy that covers everything apart from third party injury and personal injury, as this is covered by the TAC/State Government, whereas in the US it seems to refer to the equivalent of Fire & Theft. One of the other traps to watch for is many insurance policies only cover citizens and residents of the issuing country (just like the travel insurance above).
In terms of comparing the insurance I have....
In Australia - TAC plus eBike comprehensive
In EU - ADAC (which only covers third party injury) ie the minimum mandatory requirement...although personal injury was also covered through the travel insurance
In Nth America - Sunrise which covers the lot (and hence possibly doubles up with my travel insurance). Basically took the extra as they are litigous bastards. I did look at the Progressive Insurance offering, but they do not cover Canada (a big part of my trip), according to their website:
Motorcycle / ATV Insurance Availability
Progressive Direct® and Drive® Insurance from Progressive offer auto insurance quotes to customers across the United States online, by phone or via agents/brokers. There are, however, a few limitations to what’s offered — no insurance in Canada, for example.
Anyway, hope that has been useful.