Ive only been using this one and another app for like 1-2 weeks. This one has a lot of colors for free, and a small banner ads space at bottom.
Finished photo can be saved to your photo roll and then you can send the artwork via Twitter, Instagram whatever, save to wallpaper etc. There is also an option to send it by email.
As for "no eraser" - there were several options to change colors. There are four symbols at top - a left arrow at far left. The second one is a trash can, which acts like a giant eraser. (Dont worry, if you hit it by mistake, it gives you two options – the first to cancel the request, the second to reset. That will clear all the colors you had applied.).
The third tool is a circular arrow, which goes counter-clockwise. This simply works as a undo button - if you fat finger a space and put the wrong color, that symbol will reverse what you touch to the color it was previously. So it will let you undo several strokes - I think 8-10 times you can undo previous color options.
Finally, if you put color in there and then decide you dont like it, you can always select the white paint color and put it over the color you dont like. This also has the effect of using an eraser. Then as you look at what you have, you can leave it white in the areas you cant decide, until you figure out what color you do want to replace the what areas with.
Because the colors here are not additive, you cant put down the red color, for example, and then add the white to make pink. Instead, it will turn white (last color selected), and undo the red automatically. So, if you have red, and you want pink, you will need to select the pink and then add it on top of the red areas where you wanted pink.
If they dont have the exact shade you wanted, ummm I have bad news for you - this is a "wysiwyg" app. And a free one, at that - so the paint set is ultimately limited.
Im not real sure why I holding back and giving it a 4.5 instead of 5 - maybe because this app is bashful about advertising itself when I save my art and then upload to Instagram or Twitter etc. (It is not like ColorTherapy app, where you have to save and post your artwork to "unlock" new designs or new paint set options, etc.).
But for free, its pretty good, and the ad hasnt been too obtrusive. I do need to stretch the artwork out with the pinch touch to get to some of the finer details to touch (I havent found a tiny touch stylus yet!).
Enjoy !
msdrpepper about Adult Coloring Book | COLORS