The job they do can only be described as passable.
So true. PS express has nice filter effects, but that's about it.
I only use the following two on Android (dunno if they're available on Apple):
Snapseed
The best one for me to edit the basics - lighting correction, crop etc.
It boasts insanely good effects - drama, grunge, hdr, frames.
Its text-on-photo feature is all you need - different styles and colours.
Its user interface is easy and unobtrusive.
Photo Editor
This one is packed with advanced features especially for creating projects rather than just photo editing.
I use this mainly to create custom frames, and png logos with transparent background.
User interface is easy, but there's a lot to fiddle with (you don't master this one in a day).
Happy Editing!