Insurance with breakdown recovery or without?

I am just buying a small motorhome. I want to use this in the Uk and in Western Europe and in the UK for longish holidays - say a month. Is it best to get breakdown cover with the insurance or using the AA/RAC? There seems a huge difference between insurance quotes so what are the most important things I should look for? I don't want to be left stranded anywhere ever! I'd also appreciate a friendly insurer. Thank you for any help!