Flash is really not an issue with Android devices hardly ever. Mostly this is with Apple (iOS) devices and although there are "work arounds", the issue here isn't that there aren't work arounds, it's that people (the general public that is going to visit your site) may not be aware of them. That means they are on the Safari browser that is pre installed with most of the iOS devices. That means Flash does not work. Now if you use a Puffin browser as well as a few others, there are some paid browsers that do have Flash capabilities on an iOS system, but as mentioned, the general public may not be aware they even "need" to have any special apps to view your site, and that means your:
Menu
Gallery
Sliders
Etc.
Will totally be missing on your websites if they are Flash.
So you really should steer away from it if possible just so you are very sure that people are seeing your items on your page. If that means using the S-Drive system for the Photo Gallery, then so be it, I understand it works pretty well for many so whatever works it good right? Many go to jquery galleries also and those work great too. It's a preference thing in the end, but definitely shouldn't be a preference when dealing with Flash itself, it's not a user friendly iOS thing for the general public, only for those in the know that actually know they "need" something to see flash. Heck many people don't even understand there even "is" flash or what that is or that they are not even seeing things on sites, so that's the public you need to aim at for Flash work arounds.