For my day to day 'smartphone': i NEED good, stable features (email, browser, media player, phone functions). Any additional features are welcome as long as they don't introduce any instabilities.

But, to answer your real question: You can have an open platform such as maemo and still maintain a bug-free system on it aa long as the core applications get enough TLC. Herein lies the bulk of the complaints against maemo on N900. They don't have much excuse to release software codes that are inferior to iphone's original release 3 years ago (see:modest).

Ps: original iphone has 2 'killer features'; the browser and the media player (ipod software). Back then there weren't any other mobile browser with such well designed zoom/pan controls with good javascript sipport.