Recommend me an asset for level creation

Hi guys,

I have been going through assets in the Unity store that can help me get this kind of geometry, http://th05.deviantart.net/fs71/PRE/i/2013/243/4/d/3_by_prusakov-d6khb94.jpg. For my isometric game.

I narrowed down my search to ProBuilder. My biggest concern is the file size for each level. I will be developing games for mobile devices and I want to keep the file size to a minimal, because I'm planning to have at least a hundred levels. The level size will be about 4x the level on "Clash of Clan".

1). Do you guys recommend the ProBuilder asset for what I'm trying to do?

or

2). Do you have any other recommendation?