The teams I joined discourage using key: value even for a new project, despite it requires less keystrokes and is more alike JavaScript (I do not like PHP things).
Is it considered a bad style in Ruby’s community? Do not think this is subjective question. I am just asking about the common trends.
The Ruby Style Guide says “When the keys of your hash are symbols use the Ruby 1.9 hash literal syntax.”.
The main reason I use the 1.8-style syntax is that I currently use a few analysis tools that either don’t work on Ruby 1.9 (heckle … at least not yet) or don’t work as well on 1.9 (ruby-prof).