As far as I'm concerned, flash is a dying technology and for very good reasons such as:
1. File bloat
2. Insane coding concepts.
3. Apple products (iphone, ipadetc) don't support flash
While HTML5 is young, most people that you care about, have an upgraded browser.
My feeling is that smart phones will take over the world for most users.
For this reason coding in software that exports to HTML5 is not a silly idea.
If you have an issue with HTML5 export - go for one of the other game making programs on the market.
After researching quite a number of game maker tools (I even emailed the dev's of several indie games) I settled on Construct2 for these reasons:
1. It exports to HTML5 natively
2. HTML5 export is a near step to iphone and android export
3. I don't have the time to learn a 3D game making program
4. I can't be bothered to custom code - I do that enough in my day job. (after all if you are custom coding then why do you have an engine?)