I have the same boat and am in the process of considering
holding tank location and material type, etc. My old rubber one leaked. It is a small space, and a replacement rubber tank is almost as much as a new aluminum one. From what I have read, I would prefer aluminum, as my experience (smell) matches the cons of that installation(rubber). Plastic is another option, although I have not seen existing plastic tanks that would fit that space? A remote possibility, would be the dual-option aspect of aluminum, if there were access ports, and I was willing to, or needed to, go down that road.
Any thoughts or ideas on this appreciated.