I found them to be a good seller. About 3 weeks to arrive and reasonably packaged in a thick cardboard board with lots of bubble wrap. Would buy again if building another machine (!). My parts were clean and ready to use.

For info I see alot of machines using supported rail on the Z axis and whilst there is nothing wrong with that I would recommend new builders (or upgraders) to have a look at these used profile rails. Putting aside all the advantages of profile rail, their compact size makes for a neat installation in an area of the machine that benefits from compactness. And these short lengths (typically 300mm in a 15mm width) make it good value at about £80 all in.

I know what you are saying about the longer lengths. For my X axis (1300mm) I went with new supported rail from linearmotionbearings2008 (ebay).

Since the Z axis always has an unavoidable overhang I would personally go for 4 blocks.