It's truly unlimited storage, with all the things that Telegram allows, but keep in mind, as is right now it's a back up storage rather than a cloud storage service, the files cannot update yet, but it's growing rapidly
If you already use Telegram a lot, this application can be very helpful to use Telegram as some kind of 'cloud' storage for your files.
The files you can upload are only limited by the limitation of Telegram itself, eq max file size 2GB for regular Telegram users or 4GB for paid Telegram users.
This app is quite easy to use. very fast very efficient. It is updated regularly and it is unlimited cloud storage (stores it on telegram servers). If you are someone who needs space. I recommend using it!