in terms of alternatives to the zia it depends on your budget and what requirements you have for a buggy.
there's the bee which is compact when folded, adjustable handle height and even better its rearfacing but around £400 new
or the ever popular baby jogger city mini, easy to fold one handed, lovely to push and £158 in boots
maybe im just not that fussy when it comes to handle height and therefore dont mind the zia? plus mine was super cheap second hand