First off, overall quality is the same throughout the MIK E-matic lineup: different visual vibe/body size (which is a major selling point for you), but if you like the 5422 you'll also like the 5420...
Second, the '59 E-matic is only a Sweetwater exclusive in the USA market: seems it's generally available in the EU (with a slightly different, less "milky" finish), and there are more than a few hands-on reviews on YouTube - although I'm sure you already have a good idea of how it sounds, check out some of the vids for a better idea of what you're getting...
Good luck...