Lesson 2.2 - 如何

I have a quick question regarding a use of the reading いかが　vs. どう　for the word 如何 in lesson 2.2, where it's used to express "how about [a pamphlet]...?" I've heard (and used) this phrase (如何ですか）often (for example, asking children in my classes, "how about a game/review/etc.?") , but I've never heard it spoken as "ikaga," always "dou." Are these variations important? Is one a "casual" reading, or does it convey a different sentiment? Is this a regional variation?

"Dou" is more casual than "Ikaga", though both are usually written in kana alone, so you'll rarely see 如何. Also, I just noticed your name is purple.