Mezzo riders seem to like the way a Mezzo rides/folds compared to other 16" wheel folders.. 16"wheel folders will be more compact in general than 20".. The Shimano 4 speed IGH is a nice quiet hub (although discontinued) that works well for small wheel bikes as gear 1 is 1:1 and the other 3 gears are overdrive .. overall range is only 184%, so just over what a 3 speed hub would be, but obviously closer ratios between gears.. the shifter is proprietary and hard to come by.. good news is a Shimano 7 or 8 speed shifter will work in 1 through 4 .. I'd ride the Mezzo at the LBS to see if you liked it, then put in a low offer.. if it's been sitting forever there might be some incentive to clear stock.. my thinking is that a NOS I4 would be in the $300/350 range.. I had the 4 speed Shimano in a 20" folder and liked it a lot.