I have been looking at the Rossi Wizard for a while, and I am just about to buy one.
The upside you have already covered, and I agree with you. Hell, the barrels are available used for less than $100 for the most part, especially for calibers like .270, .243, and 20Ga.
The downside seems to be the "Ejector / Extractor". It does not always catch the rim of the shell, and the mechanism gets locked up.
At roughly $250 for the rifle, I am willing to roll the dice a bit. Once I get one I will post up more info. It is a great concept, and all but ban proof; an important consideration out here behind the lines.