I thought "yeah yeah, another Megatron with purple paint sloshed on and relabelled Galvatron *yawn*" but I actually like the way it turned out.
I'm not keen on the tank mode - I don't think the wings look right. How about putting purple on the middle strip of the front ones to blend them with the body so they don't look like superfluous extras? I feel they need something to blend them in.
The robot mode works very well! Those are the pics that won me over!
As for Convotron's suggestion of copper paint, this is a good idea but another option is orange drybrushed over silver. You can see how this looks on my
Unicron. The orange needs contain more red than you think it needs as it will come out more yellowy when you drybrush it so you'll need to experiment on something first to get the right colour. I find it more satisfying to have mixed my own colours cos it makes it all that little bit more unique! BTW I'm not saying my suggestion is better than Convotron's! It's your choice.