Most of my edugames run html 5, to make it more avaialble for android/window/iOS users (bypassing all the issues for publish on various stores, and it's custom for the company.
My games is not very complex, but I havnt come across any issues, and done more than 300 edu App's the past 4 years using AppGameKit classic and Studio.
I agree, HTML5 is very slow sometimes, if you have a bunch of graphics... but worth the effort to try.
Like Loktofeit said. try not to use to complicated code, then it won't be a problem.
The only thing I would LOVE in AppGameKit, is Midi support and more GUI functions
Try not to use Plugins (Which might not work) and use native code as far as possible.
I use xampps as a local testing server, and then upload to main server when done.