I agree with the other gentleman, use them both together. Use an almond sized amount of the tube in your bowl, a few whipps of the tub on your brush and mix the two together into a super lather. It will produce a far richer and creamier shaving cream than either one alone.
They are exactly the same with different consistency. This info comes directly from the manufacturer - Ludovico Martelli company. I also prefer the tub, but simply because I prefer soaps over creams.
Both are top shelf products; but I like the green tub. I find the tub to produce a slicker lather than the tube; maybe a heavier, more dense lather. I suspect that is from face lathering the tub and whipping the tube in a bowl. Again, both are excellent.
The two together is awesome. Or sometimes I shoot a bit of Jack Black Beard Lube into the bowl and then use the tub Proraso. I have found using the tub alone dosen't get my face slick enough. I will have to experiment with it a bit more...
I just emptied a tube of proraso green into a tub of proraso white (sensitive skin). It's the perfect combo. Almost the same consistency as the truefitt and hill sandalwood tub of cream. I have not yet compared them, but i'm excited for both. I'll let you know how the shave and lather comes along.