Well, just like with mechanical keyboards, the 'best' often is subjective. Depends on what the user finds important for his typewriter/keyboard. My criteria were:
-Comfortable for long writing sessions (bigger portables. segment shift, or light carriage shift)
-Great response and tactile feedback from keys. Not too heavy nor too light. Solid keyaction.
-Rare or unique machine
-Not too big for a portable, not too heavy. Around 5-6kg
-Font type and maximum words per line.
-Smoothness of carriage return
-typewriter sound when typing
-key functions, intuitive keyboard layout
-Silent as possible platen
And so on...It also depends, what sort of style the writer uses. Short story? Notes? Novels? etc.
No doubt the Alpina is very very nice to type on. But it feels somewhat all the same, from that region and era. Like the Optima Elite, Rheinmetal kst, Voss. Very desktop typewriter feel, very solid. But also a bit boring maybe, because everything is so 'well' engineered. Like classic cars and motorcycles. People want to something more adventurous, a bit more character so to speak.
Often times, I used the Princess, for its desktop feel but portable dimensions. An other is the Gossen Tippa. Gossen totally blew me away. There is no single typewriter that types so well, even better than Alpina and its brothers, is a flat portable (flat portables don't tend to type well, because of mechanical limitations, it is so flat) and is even smaller than a Kolibri. A lot of beginners only focus on the Kolibri, sm3-4 or the Valentine's. But the true underdog is the Gossen Tippa. Highly sought after, but few know of it.
The best sounding typewriter, I find is the Imperial Good Companion on my Etsy. It has relations with Torpedo Werke AG. And sounds like a Turbocharger.
