How much you enjoy the game will rely 100% on your expectations. If you're expecting it to be the best mobile game ever you'll hate it because quite frankly it's not. If however you were expecting it to be a stripped down mobile game in the "Sim Tower" type genre then you'll enjoy it. It's better than most mobile games in that genre and while I've heard tales of it crashing lots from some people I haven't had a single issue myself.
I've been playing it on my work phone (iPhone 5s) and my main complaint is that I'd prefer it on a bigger screen so I am quite looking forward to re-starting on my Note 3. The graphics are really good for a mobile game, I like the stylized Vault Boy style and the depth of the rooms.