Personally I'd stick with the devil you know and love...
But it's a matter of whether or not you want a newer car, what it will do for you etc, changing back to Petrol might save you a few pennies at the pump but over the long term will it save anything or cost more?
Both A and B series have their positives and negatives, personally speaking I love the A series and wouldn't want a B series..

Get a picture of both of them from the same angles, front, sides and rear, then sit them side by side and look at them both and see which one YOU want to have and drive and look after

Good luck.
Si