I use Project Life app on my Android. I also use "PhotoLayers" app. I like to shadow my elements in PSE, save them in Dropbox already shadowed, and then use the PhotoLayers app to put them onto my pages. PhotoLayers allows up to 10 layers, and you can shadow there, but I find it hard to manage on tiny screens.
I typically do text/journaling in the PL app, but there are others for that as well. Photofy, Rhonna Designs, Over for android will do text, but it is certainly not up to iOS version. PicsArt, PhotoGrid... I have a lot of apps. I mostly stick with PL and PhotoLayers though.
There is at least one group on facebook I participate in about App Scrapping (called "app-scrappers Project Life"). There are several tutorials around digi land.
Amber Labau's Creative Team did a series last year, so you can search her blog. The Daily Digi has a series, and that seemed to go VERY well, because Steph then went and made her own brand/class: "modern photo solutions" I think. TDP recently did a blog series. Scrapaneers has a class.... there are a TON of resources!
Here are a my app scrapping layouts... I love using Just Jaimee's stacked cards, too!