Post trip report
We've finished our trip now and after wearing the Alter Ego jacket for nearly 8 months on the road I would give it a 6-7/10 rating for this sort of usage.
For the hotter parts of the trip removing the outer shell and having a mesh jacket with the built in armour was great. But as Mollydog said the fine pitch zips were very stiff, I had the outer shell on for several months and when I removed it for the first time in Mexico I decided not to try and put it back on until I could wash the jacket (When I did that after we got back the amount of "mud" left in the bottom of the bath was incredible) and this was on a trip that was mainly all tarmac riding, no serious dirt or off road dust at all. Even after washing there I need to use more force than I care too to get the shell zipped up again.
For the colder parts of the trip it was fine and using a layered approach worked for us (thermals, heated vest, jacket, waterproof shell) wearing more layers as it got colder (or wetter).
I didn't like the inner waterproof liner supplied as the jacket willl absorb a lot of water first and it takes ages to drain away and even longer to dry. We bought separate outer rain jackets from Dri-rider that worked very well. Wearing the rain shell over the jacket made the heated vest work much more efficiently.
We got rid of our light weight fleece jackets and bought a compressor jacket from mountain hardware. This was our best buy as it was windproof, light and very warm. The best part is that it packs down into its own pocket taking up very little room when not being used. It packed down to less than half the volume the fleece did. I think that mountain hardware now only sell a version with a hood which would not be as useful for this sort of trip. (hoods flapping around while riding will annoy any pillion). Maybe other outdoors clothing people sell something similar.
And the Widder heated vest was brilliant, the only reason that we could get away with using a lighter weight jacket was due to the vest. I found that out in Alaska when I blew a fuse that powered the vests. After 15 minutes of steadily getting colder I'd had enough and fixed it on the spot instead of waiting till the end of the day.
Hope that helps any future buying decisions