Update: I am still using MosaLingua nearly every day for the past 8 months and its an excellent way to keep building my vocabulary and phrases.
In the last month Ive used about 10 different Spanish teaching or reference apps and online tools, including Duolingo, SpanishDict.com, Fluencia, CatSpanish, Mirai Spanish, & the Discover Spanish podcast. I just started with MosaLingua a few days ago. The other apps are all good but what I really like about MosaLingua is the level of customization available to the user. While it offer the basics the app also lets you select what you most want to learn. The extra articles, dialogues, quotes and jokes are quite nice features too. You can set your own pace and the app will set up your reviews accordingly. It is clear the developers have really invested in making it a great user friendly learning experience!