This game is a victim of its own fairness. You can obtain characters through the Inn, not unlike King's Raid. The difference is that one character does not take a month to unlock. You are awarded more than enough gems to hurry the process along when you really want to unlock someone. The catch is that you need hero pieces to upgrade and then materials to evolve that character. These are not as easily obtained, but can be purchased.
There are lots of costumes in the current version. Last I saw, it was around 78 different costumes ranging from 90 to 120 threads. Where do you obtain threads, though? Well, you get them from events and purchases. This means that costumes are more or less premium items, since completing an entire event will only reward enough to almost buy one costume.
The story is decent, but does get redundant. There are only so many times you can wander into a town and meet some new fighter that needs help and will be waiting at the Inn before you stop reading it. Once you stop reading, the game is just a collection of auto battle stages that require walking a little between them. There are a lot of characters, but only about 5 truly original ones that are then slightly varied with new names and outfits.
I have played this game off and on since the original release. It wasn't until I hit the point where 5* characters became ineffective and awakening materials became premium items that I realized the game really hooks you in before stranding you. In business, they call this a glass ceiling. It's something not a lot of games use because most want to maximize profits immediately at the cost of becoming obsolete in time for the next title. Once you begin waiting for the reset to gather up a few more hero pieces or a handful of evolution materials, it feels less like a game and more like a chore. Is that really what you want in a game?
This brings us to having a Tap version. While it is nice to start over and get new pre-registration rewards, what about all of the premium aspects? I can't use Google Play credit or carrier billing. Will items be cheaper without Google's fees or is this a way for the developer to keep more of the profit? Is there really any reason to release a game that is already available anywhere in the world? Do I really want to repeat hundreds of levels just to hit another stalemate?
As a new player, it is worth trying. I don't regret the time I spent playing it. Know when to stop. When you aren't upgrading your characters as part of the story and you start waiting for the reset, the game is over. Put it down, take a break, and come back later to see what has changed.