Here's a decent summary of the various ways of making engine cylinders and the advantages and disadvantages of each.
As an old fashioned engineer I'm just a tad resistant to anything I can't fix in house like Nikasil and other special coatings. Alusil can of course be rebored easily enough because it's nothing more than just a slightly fancy hardish grade of aluminium and I think you can even get special honing pads to fit normal honing equipment to expose the new silicon particles but I don't know how good a job that does compared to the factory etching process. Nikasil can be machined out, it's about 3 thou deep, as long as the bore underneath isn't damaged and re-Nikasiled but it's not cheap and I don't know how many people can even do it in the UK. Plenty in the USA of course. Even to rehone the stuff as part of a rebuild with new rings you need diamond tooling. However as a rule all of these types of engine don't even have oversize pistons listed. It's basically new engine time if anything gets fecked as far as the OEMs are concerned.
It might be heavy but you know where you stand with a nice big lump of cast iron. Easy to bore, hone, skim, drill, tap and everything else other than carry round the bloody workshop. You'll know what I mean if you've ever had to hump an MGB block onto a milling machine several times a day. Thank god I never worked on iron block V6s and V8s.
However my prejudices aside there's no disputing the fact that using all aluminium blocks saves a lot of weight and improves heat transfer considerably. Cast iron has had its day. The Nikasil Porsche engines have been extremely reliable for example.